Drilling tools

Abstract

To reduce trouble of exchanging a cutting blade and positioning involved in exchanging the cutting blade.SOLUTION: A boring tool 100 comprises: a tool body 10 which includes a center axis Z; and a cutting blade 50 which is detachably connected with the tool body 10. A virtual straight line orthogonal to the center axis Z is defined as an orthogonal straight line X; one direction of two directions along the center axis Z is defined as a forward direction ZA; and an opposite direction of the forward direction ZA is defined as a backward direction ZB. The cutting blade 50 includes: a cutting edge 71 which is positioned along the orthogonal straight line X at a portion farthest from the center axis Z; and an outmost surface 72 which is continuously extended from the cutting edge 71 in the backward direction ZB. The outmost surface 72 is a curve surface where the shortest distances from the center axis Z are the same at any point in the outmost surface 72.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a drilling tool. [Background technology]

[0002] The drilling tool of Patent Document 1 includes a tool body, two cutting blades, and two guide pads. The tool body is generally cylindrical in shape. Each cutting blade is detachably connected to the tool body. Also, each guide pad is detachably connected to the tool body. When a virtual straight line perpendicular to the central axis of the tool body is defined as an orthogonal straight line, the position of the guide pad can be adjusted in a direction along the orthogonal straight line relative to the tool body.

[0003] In cutting using the drilling tool of Patent Document 1, first, the worker adjusts the position of each guide pad relative to the tool body in accordance with the position of each cutting blade relative to the tool body. Then, the worker processes the workpiece with the cutting blades of the drilling tool while the drilling tool rotates relative to the workpiece. As a result, a hole with a radius according to the position of each cutting blade in the direction along the orthogonal straight line is formed in the workpiece. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2004-314258 A Summary of the Invention [Problem to be solved by the invention]

[0005] In a drilling tool such as that of Patent Document 1, when the cutting blade wears out due to cutting of the workpiece, it is necessary to replace the cutting blade. When replacing the cutting blade, the position of the guide pad must be adjusted, which is time-consuming. For example, instead of replacing the cutting blade, it is possible to grind the cutting blade. However, even in this case, the position of the cutting edge of the cutting blade may change, so the positional relationship between the cutting blade and the guide pad must be adjusted, which is the same effort as replacing the cutting blade. [Means for solving the problem]

[0006] A drilling tool for solving the above problems is a drilling tool comprising a cylindrical tool body having a central axis, and a cutting blade detachably connected to the tool body, wherein when a virtual straight line perpendicular to the central axis is defined as an orthogonal straight line, one of two directions along the central axis is defined as a positive direction, and the direction opposite to the positive direction is defined as a negative direction, the cutting blade comprises a cutting edge located at a point farthest from the central axis in a direction along the orthogonal straight line, and an outermost surface extending continuously from the cutting edge in the negative direction, and the outermost surface is a curved surface whose shortest distance from the central axis is equal at every point on the outermost surface.

[0007] In the above configuration, assume that the edge in the positive direction on the outermost surface is ground. At this time, the end in the positive direction of the outermost surface after grinding is exposed as a new cutting edge. And since the outermost surface is a curved surface that is equidistant from the central axis at every point, the distance from the central axis does not change between the cutting edge before grinding and the cutting edge after grinding. Therefore, with the above configuration, when the cutting edge becomes worn, it is sufficient to grind it, and there is no need to replace the cutting edge or adjust its position associated with the replacement.

[0008] In the above configuration, a plurality of the cutting blades may be provided, and the shortest distances from the central axis to the outermost surface may be the same for each of the plurality of cutting blades. In cutting using the above-mentioned drilling tool, when one of the cutting blades is focused on, a force toward the central axis, a so-called thrust force, acts on the cutting blade during cutting. According to the above-mentioned configuration, the thrust force acting on a specific cutting blade can be received by the outermost surface of the other cutting blade contacting the inner peripheral surface of the hole in the workpiece. Therefore, it is possible to suppress the occurrence of runout in the central axis of the tool body when the thrust force acts.

[0009] In the above configuration, the tool body includes a connecting portion to which the cutting blade is connected, and a protruding portion protruding from the end face of the connecting portion on the positive side, the cutting blade being connected to the end of the connecting portion on the positive side, and the protruding portion may have a circular reference curved surface whose shortest distance from the central axis is equidistant at every point.

[0010] According to the above configuration, by contacting a measuring device such as a dial gauge with the reference curved surface of the protrusion, the drilling tool can be positioned so that the central axis of the tool body coincides with the reference axis. At this time, since the protrusion used for positioning is located near the cutting blade, the positioning accuracy in the vicinity of the cutting blade is high. If the cutting blade is ground in this state, the positional accuracy of the cutting blade after grinding is also high.

[0011] In the above configuration, the cutting blade may be connected to the tool body in a state where its position cannot be adjusted in a direction along the orthogonal straight line. According to the above configuration, for example, when performing cutting processing using a drilling tool, when sharpening the cutting blade, etc., the cutting blade is not displaced unintentionally in the direction along the orthogonal straight line. In other words, the position of the cutting blade does not change in the direction along the orthogonal straight line.

[0012] In the above configuration, the entire outermost surface may be made of a material containing diamond. According to the above-mentioned configuration, if even a part of the outermost surface remains, it can be ground to expose a new cutting edge. Therefore, the cutting edge can be repeatedly ground and used.

[0013] In the aforementioned configuration, a dimension of the outermost surface in a direction along the central axis may be 1 mm or more. According to the above configuration, a certain amount of grinding allowance is secured in the direction along the central axis on the outermost surface, so that even if only a portion of the outermost surface in the positive direction is ground, the end of the outermost surface in the positive direction after grinding can be easily used as a new cutting edge. [Brief description of the drawings]

[0014] [Figure 1] FIG. [Diagram 2] FIG. 2 is a left side view of the boring tool in FIG. 1 . [Diagram 3] An enlarged view of the cutting blade in Figure 1. [Figure 4] 4 is a bottom view of the cutting blade in FIG. 3 . [Diagram 5] An enlarged view of the cutting blade in Figure 2. [Figure 6] FIG. 4 is an explanatory diagram showing a method for polishing a boring tool. [Figure 7] FIG. 4 is an explanatory diagram showing a method for polishing a boring tool. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] <Boring tool configuration> A boring tool 100, which is one embodiment of a drilling tool, will be described below with reference to Figures 1 to 7. First, a schematic configuration of the boring tool 100 will be described.

[0016] As shown in FIG. 1, the boring tool 100 includes a tool body 10. The tool body 10 has a generally cylindrical shape. Therefore, the tool body 10 has a central axis Z passing through the center of gravity of the tool body 10. In the following, one of two directions along the central axis Z of the tool body 10 is defined as a positive direction ZA, and the opposite direction to the positive direction ZA is defined as a negative direction ZB. The positive direction ZA is the left side in FIG. 1, and the negative direction ZB is the right side in FIG. 1. Also, as shown in FIG. 2, a virtual straight line perpendicular to the central axis Z is defined as an orthogonal straight line X.

[0017] 1, the tool body 10 includes a protrusion 20, a connecting portion 30, a cylindrical portion 35, a shank 40, and a retaining bolt 45. The cylindrical portion 35 has a substantially cylindrical shape. The central axis of the cylindrical portion 35 coincides with the central axis Z.

[0018] The shank 40 extends from the end face of the cylindrical portion 35 in the negative direction ZB. The shape of the shank 40 is tapered such that the outer diameter decreases toward the negative direction ZB. The central axis of the shank 40 coincides with the central axis Z. The shank 40 has a bolt hole 41. The bolt hole 41 is recessed from the end face of the shank 40 in the negative direction ZB. The shape of the bolt hole 41 is approximately cylindrical. The central axis of the bolt hole 41 coincides with the central axis Z. Although not shown in the figure, the inner peripheral surface of the bolt hole 41 has a helical thread groove.

[0019] The retaining bolt 45 is connected to the shank 40. The retaining bolt 45 is rod-shaped as a whole. The central axis of the retaining bolt 45 coincides with the central axis Z. Although not shown, the outer peripheral surface of the retaining bolt 45 has a thread groove. A part of the retaining bolt 45, including the end on the positive direction ZA side, is screwed into the bolt hole 41. As a result, a part of the retaining bolt 45, including the end on the negative direction ZB side, protrudes from the end face of the shank 40 in the negative direction ZB. The shank 40 and the retaining bolt 45 are parts that are held by the machine tool when the boring tool 100 is attached to the machine tool. An example of the machine tool is a machining center.

[0020] The connecting portion 30 extends from the end face of the cylindrical portion 35 in the positive direction ZA. The connecting portion 30 is substantially cylindrical in shape. The outer diameter of the connecting portion 30 is larger than the outer diameter of the cylindrical portion 35. The central axis of the connecting portion 30 coincides with the central axis Z. The connecting portion 30 has three chip pockets 31. The chip pockets 31 are recessed in the outer circumferential surface of the connecting portion 30. The chip pockets 31 reach the end face of the connecting portion 30 in the positive direction ZA. As shown in FIG. 2, the three chip pockets 31 are positioned at equal intervals in the circumferential direction around the central axis Z.

[0021] As shown in FIG. 1, the protrusion 20 protrudes from the end face of the connecting portion 30 in the positive direction ZA. The shape of the protrusion 20 is substantially cylindrical. The outer diameter of the protrusion 20 is smaller than the outer diameter of the connecting portion 30. The central axis of the protrusion 20 coincides with the central axis Z. Therefore, the outer peripheral surface of the protrusion 20 is an annular reference curved surface 20A in which the shortest distance from the central axis Z is the same at any point on the outer peripheral surface. The protrusion 20 has a central recess 21. The central recess 21 is recessed from the end face of the protrusion 20 in the positive direction ZA. The shape of the central recess 21 is a tapered shape in which the inner diameter becomes smaller toward the negative direction ZB. The central axis of the central recess 21 coincides with the central axis Z.

[0022] 2, the boring tool 100 has three cutting blades 50. The cutting blades 50 are connected to an inner wall surface of the connecting portion 30 that defines the chip pocket 31. Therefore, the three cutting blades 50 are positioned at equal intervals in the circumferential direction centered on the central axis line Z. The cutting blades 50 are positioned at the ends of the connecting portion 30 in the positive direction ZA. The cutting blades 50 are also positioned on the outer periphery of the connecting portion 30.

[0023] One of the three cutting blades 50 is located on the orthogonal straight line X shown in Fig. 2. All three cutting blades 50 have the same configuration. Therefore, the cutting blade 50 located on the orthogonal straight line X will be described below. The cutting blade 50 is connected to the connecting portion 30 in a state where its position cannot be adjusted in the direction along the orthogonal straight line X.

[0024] As shown in FIG. 4, the cutting blade 50 includes a substrate 60, a blade material 70, and a base metal 80. As shown in FIG. 3, the base metal 80 is plate-shaped. When viewed from a direction perpendicular to the main surface of the base metal 80, the shape of the base metal 80 is a substantially rhombus shape. The main surface of the base metal 80 is the largest flat surface portion of the surface of the base metal 80. The end face of the base metal 80 in the positive direction ZA protrudes from the end face of the connecting portion 30 in the positive direction ZA. In addition, the outer peripheral surface of the base metal 80 on the opposite side to the central axis Z, i.e., the lower surface in FIG. 3, protrudes outward from the outer peripheral surface of the connecting portion 30.

[0025] The base metal 80 has a through hole 81 and a recess 82. The through hole 81 penetrates the base metal 80. The base metal 80 is connected to the connecting part 30 by inserting a screw (not shown) into the through hole 81. The base metal 80 can be removed from the connecting part 30 by removing the screw. Therefore, the cutting blade 50 is detachable from the connecting part 30.

[0026] The recess 82 is recessed from the main surface of the base metal 80. The recess 82 is located in a portion of the base metal 80 including the end in the positive direction ZA. The recess 82 extends over the entire edge of the base metal 80 in the positive direction ZA.

[0027] As shown in Fig. 5, the substrate 60 is plate-shaped. The substrate 60 is fixed to the inner surface of the recess 82 of the base metal 80. As shown in Fig. 4, the end face of the substrate 60 in the positive direction ZA protrudes from the end face of the base metal 80 in the positive direction ZA. In addition, the end face of the substrate 60 in the positive direction ZA is aligned along the orthogonal straight line X.

[0028] Here, the surface of the substrate 60 opposite to the central axis Z, i.e., the lower surface in Fig. 5, is defined as the outer peripheral surface 62. As shown in Fig. 5, the outer peripheral surface 62 protrudes from the portion of the base metal 80 that is the farthest from the central axis Z in the direction along the orthogonal straight line X. The outer peripheral surface 62 is along the central axis Z. An example of the material of the substrate 60 is a cemented carbide. The cemented carbide is a mixture of tungsten carbide, cobalt, etc., sintered.

[0029] As shown in Fig. 5, the blade material 70 is plate-shaped. As shown in Fig. 3, the shape of the blade material 70 when viewed from a direction perpendicular to the main surface of the blade material 70 is substantially the same as the shape of the base material 60 when viewed from a direction perpendicular to the main surface of the base material 60. The blade material 70 is fixed to the main surface of the base material 60. That is, the blade material 70 overlaps the base material 60. As shown in Fig. 4, the end face of the blade material 70 in the positive direction ZA is flush with the end face of the base material 60 in the positive direction ZA. That is, the end face of the blade material 70 in the positive direction ZA is aligned with the orthogonal straight line X.

[0030] Here, the surface of the blade material 70 opposite to the central axis Z, i.e., the lower surface in Fig. 5, is defined as the outermost surface 72. As shown in Fig. 5, the outermost surface 72 protrudes from the outer peripheral surface 62 of the base material 60 on the opposite side of the central axis Z. Therefore, the end of the positive direction ZA on the edge of the outermost surface 72 is the portion where the workpiece is cut when the workpiece is actually cut. In other words, the end of the positive direction ZA on the edge of the outermost surface 72 is the cutting edge 71 located at the portion farthest from the central axis Z in the direction along the orthogonal straight line X.

[0031] 3, the outermost surface 72 extends continuously from the cutting edge 71 in the negative direction ZB. The outermost surface 72 has the same shortest distance from the central axis Z at any point. In other words, the outermost surface 72 is a part of the outer peripheral surface of an imaginary cylinder centered on the central axis Z.

[0032] In this embodiment, the thickness of the blade material 70 is, for example, about 0.8 mm. The dimension of the outermost surface 72 in the direction along the central axis Z is, for example, 4 mm. The material of the blade material 70 is, for example, sintered diamond, commonly known as PCD. That is, the entire area of ​​the outermost surface 72 is made of a material containing diamond.

[0033] As described above, in this embodiment, the three cutting blades 50 have the same configuration. The two cutting blades 50 that are not located on the orthogonal line X are also similar in that they are located on another orthogonal line that is perpendicular to the central axis Z and intersects the orthogonal line X. The three cutting blades 50 are in a three-fold symmetric relationship with respect to the central axis Z. Therefore, the shortest distances from the central axis Z to the outermost surfaces 72 of the three cutting blades 50 are the same for each other.

[0034] <Action of this embodiment> First, the grinding device 200 used to grind the cutting blade 50 of the boring tool 100 will be described.

[0035] As shown in FIG. 6, the grinding device 200 includes a first center shaft 210, a second center shaft 220, and a grindstone 230. The first center shaft 210 includes a first support portion 211 and a first tip portion 212. The first tip portion 212 protrudes from the first support portion 211 toward the second center shaft 220. The first tip portion 212 has a tapered shape in which the outer diameter becomes smaller toward the tip. The first tip portion 212 is rotatable with respect to the first support portion 211 around a rotation axis 212Z of the first tip portion 212. The second center shaft 220 has the same configuration as the first center shaft 210, except that it is disposed symmetrically to the first center shaft 210. That is, the second center shaft 220 includes a second support portion 221 and a second tip portion 222. The second tip portion 222 protrudes from the second support portion 221 toward the first center shaft 210. Further, the rotation axis of the second tip portion 222 coincides with the rotation axis 212Z of the first tip portion 212. The shape of the grindstone 230 is a substantially circular disk shape. The grindstone 230 is rotatable about the rotation axis 230Z of the grindstone 230. The rotation axis 230Z of the grindstone 230 is parallel to the rotation axis 212Z of the first tip portion 212. The grindstone 230 is movable relative to the first center shaft 210 and the second center shaft 220 while maintaining the parallel state of the rotation axis 230Z and the rotation axis 212Z.

[0036] Next, a method for grinding the outermost surface 72 of the boring tool 100 using the grinding device 200 will be described. First, the worker removes the retaining bolt 45 of the boring tool 100 from the shank 40. The worker sandwiches the boring tool 100 between the first center shaft 210 and the second center shaft 220 and supports it on the grinding device 200. Specifically, the worker inserts the first tip 212 of the first center shaft 210 into the central recess 21 of the protruding portion 20. The worker also inserts the second tip 222 of the second center shaft 220 into the bolt hole 41 of the shank 40. At this time, the worker positions the boring tool 100 so that the central axis Z of the boring tool 100 and the rotation axis 212Z of the grinding device 200 coincide with each other. As a specific example, the worker brings the measuring part of the dial gauge 300 into contact with the reference curved surface 20A of the protruding portion 20. Then, the worker rotates the boring tool 100 and checks the scale of the dial gauge 300 to position the boring tool 100 so that the central axis Z of the boring tool 100 coincides with the rotation axis 212Z of the grinding device 200. Similarly, the worker positions the boring tool 100 by bringing the measuring portion of the dial gauge 300 into contact with the outer circumferential surface of the cylindrical portion 35 and the outer circumferential surface of the shank 40, so that the central axis Z of the boring tool 100 coincides with the rotation axis 212Z of the grinding device 200.

[0037] After the boring tool 100 is positioned, as shown in FIG. 7, the grindstone 230 is moved in a direction along the orthogonal line X to the outside of the cutting blade 50 of the boring tool 100, that is, to the side farther from the central axis line Z. Also, when viewed from the direction along the orthogonal line X, the grindstone 230 is moved to a position where the grindstone 230 overlaps with a part of the outermost surface 72 of the cutting blade 50, including the end in the positive direction ZA. At this time, an example of a dimension where the grindstone 230 overlaps with the outermost surface 72 of the cutting blade 50 in the direction along the central axis line Z is about 0.1 mm to 0.5 mm. In other words, the length along the central axis line Z for grinding the cutting blade 50 in one grinding is about 0.1 mm to 0.5 mm. Then, the operator rotates the grindstone 230 around the rotation axis line 230Z. Further, the worker moves the grindstone 230 in the direction along the orthogonal line X so as to approach the central axis Z, as shown by the two-dot chain arrow in FIG. 7. Here, the worker grinds the blade material 70 of the cutting blade 50 by moving the grindstone 230 to a position where the grindstone 230 and the blade material 70 of the cutting blade 50 overlap in the direction along the orthogonal line X when viewed from the direction along the central axis Z. At this time, an example of the dimension where the grindstone 230 and the blade material 70 of the cutting blade 50 overlap in the direction along the orthogonal line X is about 0.1 mm to 1 mm. In other words, the length in the direction along the orthogonal line X for grinding the cutting blade 50 in one grinding is about 0.1 mm to 1 mm. Similarly, the blade materials 70 of the remaining two cutting blades 50 out of the three cutting blades 50 are ground.

[0038] <Effects of this embodiment> (1) When the edge in the positive direction ZA of the outermost surface 72 of the cutting blade 50 is ground as described above, the end in the positive direction ZA of the outermost surface 72 after grinding is exposed as a new cutting edge 71. Here, since the outermost surface 72 of the cutting blade 50 is a curved surface that is equidistant from the central axis Z at any point, the distance from the central axis Z does not change between the cutting edge 71 before grinding and the cutting edge 71 after grinding. Therefore, according to the boring tool 100, when the cutting edge 71 is worn, it is only necessary to grind it, and there is no need to replace the cutting blade 50 or adjust the position of the cutting edge 71 associated with the replacement.

[0039] (2) In this embodiment, the boring tool 100 is positioned so that the central axis Z of the boring tool 100 coincides with the rotation axis 212Z of the grinding device 200 by contacting the measuring part of the dial gauge 300 with the reference curved surface 20A of the protruding part 20. Here, the protruding part 20 protrudes from the end face of the connecting part 30 in the positive direction ZA, and the cutting blade 50 is connected to the end of the connecting part 30 in the positive direction ZA. That is, since the protruding part 20 used for positioning is located near the cutting blade 50, the accuracy of the positioning in the vicinity of the cutting blade 50 is high. Therefore, if the cutting blade 50 is ground in this state, the position accuracy of the cutting edge 71 after grinding can also be increased.

[0040] (3) In this embodiment, the cutting blade 50 is connected to the connecting part 30 in a state where its position cannot be adjusted in the direction along the orthogonal line X. Therefore, for example, when performing cutting using the boring tool 100, or when grinding the cutting blade 50 of the boring tool 100, the cutting blade 50 will not be displaced unintentionally in the direction along the orthogonal line X. In other words, the position of the cutting edge 71 will not change in the direction along the orthogonal line X.

[0041] (4) In this embodiment, the edge in the forward direction ZA of the outermost surface 72 of the cutting blade 50 before grinding is ground to expose a new cutting edge 71. Therefore, if even a part of the outermost surface 72 of the cutting blade 50 remains, it is possible to repeatedly expose a new cutting edge 71 by grinding. Here, the entire outermost surface 72 is made of a material containing diamond. In other words, in anticipation of repeatedly grinding and using the cutting blade 50, the entire outermost surface 72 is made to function as the cutting edge 71.

[0042] (5) In this embodiment, the dimension of the outermost surface 72 in the direction along the central axis Z is 4 mm. That is, a certain amount of grinding allowance is secured in the direction along the central axis Z in the outermost surface 72. Therefore, even if a part of the outermost surface 72, including the end in the positive direction ZA, is ground, the end in the positive direction ZA of the ground outermost surface 72 can be easily used as a new cutting edge 71.

[0043] (6) In cutting processing using the boring tool 100, let us consider one of the three cutting blades 50. At this time, when cutting with that cutting blade 50, a force toward the central axis Z, so-called a thrust force, acts on that cutting blade 50. Here, the thrust force acting on a specific cutting blade 50 can be received by the outermost surface 72 of the other cutting blades 50 coming into contact with the inner peripheral surface of the hole in the workpiece. Therefore, it is possible to suppress runout of the central axis Z of the tool body 10 when the thrust force acts.

[0044] <Example of change> This embodiment can be modified as follows: This embodiment and the following modifications can be combined with each other to the extent that there is no technical contradiction.

[0045] In the above embodiment, the number of cutting edges 50 may be changed. For example, the boring tool 100 may include two or fewer cutting edges 50, or may include four or more cutting edges 50.

[0046] In the above embodiment, the connection configuration of the cutting blade 50 to the connecting portion 30 may be changed. For example, the cutting blade 50 does not necessarily need to be connected to the end of the connecting portion 30. As long as the cutting blade 50 protrudes outward from the outer circumferential surface of the connecting portion 30, it is possible to drill a hole in the workpiece and adjust the diameter of the hole.

[0047] For example, the cutting blade 50 may be connected to the connecting portion 30 by adhesion. In this case, too, the cutting blade 50 is detachable from the connecting portion 30 as long as the cutting blade 50 can be removed from the connecting portion 30.

[0048] In the above embodiment, the cutting blade 50 may be adjustable in position relative to the connecting portion 30. For example, the cutting blade 50 may be adjustable in position relative to the connecting portion 30 in a direction along the central axis Z. By connecting the cutting blade 50 to the connecting portion 30 via a cartridge or the like, a configuration in which the cutting blade 50 is adjustable in position relative to the connecting portion 30 can be realized.

[0049] The cutting blade 50 may be adjustable in position relative to the connecting portion 30 in the direction along the perpendicular straight line X. Even in this case, if it is desired to form holes of the same diameter, grinding can be performed without adjusting the position.

[0050] In the above embodiment, the material of the cutting blade 50 may be changed. For example, the material of the base material 60 may be a sintered diamond body. For example, the material of the blade material 70 may be a cemented carbide alloy.

[0051] In the above embodiment, the shape of the cutting blade 50 may be changed. For example, the dimension of the outermost surface 72 in the direction along the central axis Z may be shorter or longer than 4 mm. Considering that the cutting blade 50 is ground one or more times before use, the dimension of the outermost surface 72 in the direction along the central axis Z, i.e., the grinding allowance, is preferably 1 mm or more.

[0052] In the above embodiment, the configuration of the tool body 10 may be changed. For example, the protruding portion 20 may be omitted. In this configuration, when grinding the boring tool 100, for example, the measuring portion of the dial gauge 300 may be brought into contact with the outer circumferential surface of the cylindrical portion 35 and the outer circumferential surface of the shank 40 to position the boring tool 100.

[0053] In the above embodiment, the method of sharpening the boring tool 100 using the sharpening device 200 may be changed. For example, when the boring tool 100 is supported by the sharpening device 200, the shank 40 and the retaining bolt 45 may be held. That is, in this case, it is not necessary to remove the retaining bolt 45 from the shank 40. Also, for example, the length of the cutting blade 50 sharpened in one sharpening may be appropriately changed according to the configuration of the cutting blade 50, the shape of the hole in the workpiece, etc.

[0054] In the above embodiment, the drilling tool is not limited to the boring tool 100. For example, the present technology may be applied to a drill. [Explanation of symbols]

[0055] X: Perpendicular line Z…Center axis line ZA: Positive direction ZB…Negative direction 10...Tool body 20...Protrusion 20A…Standard curved surface 21…Central recess 30...Connection part 31…Chip pocket 35…Cylindrical section 40…Shank 41…Bolt hole 45…Retaining bolt 50…Cutting blade 60...Base material 70…Blade material 71…Cutting edge 72…Outermost surface 80...base money 100...Boring tools 200...polishing equipment 210…First center axis 212Z…Rotation axis 220…Second center axis 230…Whetstone 230Z…Rotation axis 300…Dial gauge

Claims

1. A cylindrical tool body having a central axis; A cutting blade removably connected to the tool body; A drilling tool comprising: When a virtual line perpendicular to the central axis is defined as an orthogonal line, one of two directions along the central axis is defined as a positive direction, and the direction opposite to the positive direction is defined as a negative direction, The cutting blade is A cutting edge located at a position farthest from the central axis in a direction along the orthogonal straight line; and an outermost surface extending continuously from the cutting edge in the negative direction; the outermost surface is a curved surface having an equal shortest distance from the central axis at any point on the outermost surface, The tool body includes: A connecting portion to which the cutting blade is connected; a protrusion protruding from an end surface of the connecting portion on the positive direction side, The cutting blade is connected to an end of the connecting portion in the positive direction, The protruding portion has a circular reference curved surface, the shortest distance from the central axis being the same at every point. Drilling tools.

2. A cutting blade including a plurality of the cutting blades; The shortest distance from the central axis to the outermost surface of each of the cutting blades is the same.

2. A drilling tool according to claim 1.

3. The cutting blade is connected to the tool body in a state where its position cannot be adjusted in a direction along the orthogonal straight line. A drilling tool according to claim 1 or 2.

4. The entire outermost surface is made of a material containing diamond. A drilling tool according to any one of claims 1 to 3.

5. The dimension of the outermost surface in the direction along the central axis is 1 mm or more. A drilling tool according to any one of claims 1 to 4.

Images