JP2016078209A - drill - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that in a drill which perforates a work-piece, reduction in time for cutting processing, improvement in rigidity of the drill, and prevention of breakage of the drill caused by a failure in cut chip exhaust and winding of cut chips are desired.SOLUTION: Cutting edges (4) are formed of intersecting lines (4) between flank faces (6) constituted of an end face (2a) of a tip part (2) of a drill (1) and rake faces (7) continuous to cut chip exhaust grooves (5). On the rake faces continuing from the intersecting line are formed parallely recessed curvilinear cross sections (17), whose cross sections are curvilinear, which continue from recessed curvilinear parts of the intersecting lines and are in the same straight line and preferably in a direction parallel to a shaft direction of a rotary shaft (Qr), so that the intersecting lines on the flank face are formed in a shape in which two or more recessed curvilinear parts (15) recessed toward a rotating direction are consecutively arrayed, and have a shape in which one or more protruding parts (16) formed by directly connecting ends of the adjacent recessed curvilinear parts protruding in the rotating direction to each other are formed.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a drill that is a tool for making a hole in the direction of the rotation axis of a tool that rotates relative to a workpiece.

  In general, a drill is formed at a conical tip formed at the tip of a rod-shaped drill body, a shank serving as a handle held by a rotary drive device at the base of the drill body, and a tip of the drill body. And a groove (hereinafter referred to as a chip discharge groove) for discharging the chips formed on the outer peripheral surface of the body (hereinafter referred to as the body portion) of the drill body and cut by the cutting edge to the outside. And a tool for making a hole in the direction of the rotation axis of the drill against the workpiece by rotating the drill body around the axis of the drill body and pressing the tip of the drill body against the workpiece. It is. Here, the hole processed by the drill includes a through hole, a hole with a bottom, and the like.

  The cutting edge of a drill consists of the intersection line between the flank formed in the end surface of the front-end | tip part of a drill, and the rake face which follows a chip discharge groove. The intersection line is, for example, between the corner of the chisel edge formed at the center of rotation of the tip part and the outer periphery corner formed by the point where the outer periphery of the drill intersects with the cutting edge, and is a simple straight line. There are many. In addition, the rake face that continues from the cutting edge is formed so as to follow a chip discharge groove formed in a spiral shape from the distal end side to the base side of the drill on the outer peripheral surface of the drill body, for example. The rake angle is formed so as to gradually increase from the center side toward the outer peripheral corner side, and is formed like a twisted surface. Chips cut by such a cutting edge curl sideways because the cutting speed is easily different between the rotation center side and the peripheral corner side of the cutting edge. In addition, since the cutting speed is faster than the cutting speed, the chips are easily caught in the inner surface of the hole that is cut so as to curl upward. Further, for example, if the rake face is a twisted face, the chips become conical spiral chips.

  In such a drill, for example, if thick chips are continuously generated due to the material of the workpiece, the chips may wrap around the drill and break the drill. Therefore, in the drilling tool of Patent Document 1, when the tip portion is viewed from the flank side, the shape of the cutting edge formed by the line of intersection of the flank and the rake face is sequentially increased from the rotation center of the drill body toward the outer peripheral side. It is disclosed that two or more smooth convex curve portions and smooth concave curve portions are formed, and the convex curve portions are protruded ahead of the concave curve portion in the cutting rotation direction.

  In the drilling tool disclosed in Patent Document 1, chips are generated corresponding to the convex curve portion and the concave curve portion of the cutting edge, and the chips generated from the convex curve portion are pushed apart by the convex curved surface portion of the rake face and finely divided. The chip generated from the concave curve portion extends in a circular arc shape corresponding to the concave curve portion, and is pressed against the convex curved surface portion adjacent to the concave curve portion and positioned closer to the center of rotation than the concave curve portion. It is curled suddenly and cut into fan-shaped pieces. In addition, the chips interfere with the chips generated from the portion of the adjacent convex curve portion on the concave curve portion side, and the chips generated from the concave curve portion are more reliably divided. In addition, since two or more convex curve portions and concave curve portions are sequentially provided, chips generated from the cutting blade are further finely divided. As a result, it is possible to prevent the chips from being wound around the drill and breaking the drill, or the chips from rubbing against the wall surface of the hole to deteriorate the surface roughness of the hole.

Japanese Utility Model Publication No. 62-008973

  However, the drill is not limited to the drilling tool disclosed in Patent Document 1, and further increase in the cutting speed is desired. In addition, for example, in a drill having a small diameter such as making a fine hole having a diameter of 1.0 mm or less, it is suitable for the outside of the hole being cut without clogging chips in the hole being cut. It is desirable to discharge the chips that have been divided into sizes so that the chips do not wrap around the drill and break the drill, and the surface roughness of the hole after processing is not deteriorated. In addition, with a small-diameter drill for performing such fine drilling, there is a limit to fine processing for a small cutting edge.

  Therefore, the drill of the present invention has a cutting edge shape that can be easily machined from a drill with a large diameter to a drill with a small diameter, while reducing the cutting resistance and further increasing the cutting speed. An object of the present invention is to reliably discharge the waste while dividing it into an appropriate size, prevent the chips from being wound and break the drill, and increase the rigidity of the cutting edge.

  In the drill according to the present invention, the workpiece is cut with the cutting edge at the tip and discharged from the chip discharge groove at the body by rotating around the axis and moving forward in the axial direction. A drill for making a hole in the workpiece in the axial direction, wherein the cutting edge is a line of intersection between a flank formed by an end face of the tip and a rake face following the chip discharge groove The adjacent concave curve portions that have a shape in which two or more concave curve portions in which the intersecting line on the flank face is concave in the direction of rotation and are convex in the direction of rotation are formed. The cross-section is a concave curve and the same straight line from each concave curve portion of the intersection line to the rake face continuing from the intersection line so as to have a shape having one or more convex portions formed by directly connecting the ends of the intersection line It is characterized by forming each concave curved cross-sectional groove in the direction side by side To.

  In the drill of the present invention, the concave curved cross-sectional grooves in a direction parallel to the axial direction of the rotating shaft may be formed side by side.

  In the drill of the present invention, it is preferable that each of the concave curved cross-section grooves is processed with a cutting tool made of polycrystalline sintered diamond (PCD).

  The drill of the present invention has a shape in which the cutting edge is formed by an intersection line between the flank face and the rake face, and two or more concave curve portions in which the intersection line on the flank face is concave in the direction of rotation are arranged side by side. And the rake face that follows the cutting line forming the cutting line so as to have a shape having one or more convex parts formed by directly connecting the ends of adjacent concave curves that are convex in the direction of rotation. Continuing from each concave curve section, the cross section is a concave curve and each concave curve cross-sectional groove in the same linear direction is formed side by side, so that it is the shape of a cutting edge that can be easily processed, but the same straight line aligned on the rake face Direction, preferably each concave curved cross-section groove in a linear direction parallel to the axial direction of the rotation axis, the rake angle is almost the same from the rotation center side of the drill to the outer corner side, and the rake face is not twisted, Each position on the cutting edge by the concave curve of the cutting edge Since the vertical direction of the cutting edge in the direction differs depending on the position, the outflow angle also disappears, so that the chips discharged as pushed out to such a rake face are curled sideways and upward, Depending on the type of material of the workpiece, it is formed in a straight shape or a zigzag shape in which the cross section in the continuous direction of chips is folded, Furthermore, the cross-section perpendicular to the direction in which the chips are continuous is formed in a shape in which a plurality of concave curve portions that are the same as the cutting edge are arranged, and when it receives external force while the chips are discharged, Thus, an appropriate gap can be secured without clogging the chips in the chip discharge groove, and the chips can be divided and discharged to a size that is easily discharged to the outside of the chip discharge groove. Further, in the drill of the present invention, the chips are easily broken and can be divided and reliably discharged. Therefore, it is possible to prevent the chips from being wrapped around the drill and being broken. It is possible to increase the cutting speed by increasing the depth of the groove, that is, by forming a larger cross section of the chip discharge groove perpendicular to the rotation axis of the drill to facilitate chip discharge. To. Further, in the drill of the present invention, the cutting force is reduced by forming the convex portion formed by directly connecting the ends of adjacent concave curves that are convex in the direction of rotation of the drill, It is possible to shorten the cutting time by increasing the cutting speed, and it is possible to suppress wear of the cutting edge. Further, in the drill of the present invention, it is possible to increase the rigidity of the cutting edge by preferably forming the concave curved cross-section grooves in a linear direction parallel to the axial direction of the rotation axis on the rake face. . Further, in the drill of the present invention, a wedge having a cutting edge, a flank, and a rake face, which is a part of the tip of the drill, has a concave cross-section and a straight concave curved cross-section groove continuously arranged in parallel. Therefore, the present invention can be applied even to a drill having a small diameter that is easy to break, especially when chips are wound during cutting.

The schematic of the EE arrow of FIG. 2 mentioned later which looked at the drill of this invention toward the axial direction of the rotating shaft of the said drill from the front-end | tip part is shown. The schematic of the DD arrow of FIG. 1 which looked at the front-end | tip part of the drill of this invention from the side is shown. Sectional drawing of the recessed part curve part of the cutting edge of the drill of this invention is shown, FIG. (A) is A1-A1 arrow sectional drawing of FIG. 2, FIG. (B) is B1-B1 arrow sectional drawing of FIG. (C) shows the C1-C1 arrow sectional view of FIG. Sectional drawing of the convex part of the cutting edge of the drill of this invention is shown, FIG. (A) is A2-A2 arrow sectional drawing of FIG. 2, FIG. (B) is B2-B2 arrow sectional drawing of FIG. FIG. 2C shows a cross-sectional view taken along the line C2-C2 in FIG. FIG. 1 shows a schematic diagram of a part of chips discharged when a work piece is drilled with a drill of the present invention, FIG. 1 (a) shows a schematic diagram of a part of a zigzag-shaped chip folded, FIG. (B) shows the schematic of a part of straight-shaped chip. The schematic of the EE arrow of FIG. 7 mentioned later which looked at the conventional drill toward the axial direction of the rotating shaft of the said drill from the front-end | tip part is shown. The schematic of DD arrow of FIG. 6 which looked at the front-end | tip part of the conventional drill from the side is shown. Sectional drawing of the concave curve part of the cutting edge of the conventional drill is shown, FIG. (A) is AA arrow sectional drawing of FIG. 7, FIG. (B) is BB arrow sectional drawing of FIG. The figure (c) shows CC sectional view taken on the line of FIG.

  An embodiment in which the drill of the present invention is applied to the twist drill shown in FIGS. 1 to 4 will be described as an example. The schematic diagram showing a part of the chips shown in FIG. 5 shows an example of the chips discharged when the workpiece is drilled with the drill of the present invention. In addition, the embodiment of the twist drill shown in FIGS. 6 to 8 shows an embodiment of a conventional drill, and the same components are denoted by the same reference numerals.

  The drill 1 shown in FIGS. 1 to 4 has a rod shape such as a columnar shape, and has a conical tip 2 at the tip and a shank not shown in the base. The drill 1 has a cutting edge 4 for cutting a workpiece (not shown). If the drill 1 is a twist drill 1 according to the embodiment, a pair of cutting edges 4 are formed at the tip 2 of the drill 1. A pair of chip discharge grooves 5 for discharging the chips 20 after cutting with the cutting edge 4 to the outside are formed on the outer peripheral surface 3a of the body 3 of the drill 1 from the tip side to the base side. It is formed in a spiral shape. Therefore, the drill 1 has a shank held by, for example, a drill driving device (not shown) for rotating and advancing and retracting the drill 1, and the rotation axis Qr while rotating with the axis of the drill 1 as the rotation axis Qr. By moving forward with respect to the workpiece in the axial direction, a hole (not shown) in the axial direction of the rotation axis Qr is formed in the workpiece.

  The conical tip portion 2 has a pair of flank surfaces 6 formed on the end surface 2a on the tip side and a pair of rake surfaces 7 respectively connected to the chip discharge grooves 5, and the flank surfaces 6 and the flank surfaces thereof. It has a pair of cutting edges 4 consisting of each line of intersection 4 between the rake faces 7 corresponding to the face 6 and a chisel edge 8 consisting of a line of intersection between a pair of adjacent flank faces 6. The flank 6 is provided to avoid friction between the work surface of the workpiece and the end surface 2a of the tip 2 of the drill 1 when the cutting edge 4 cuts into the work. It is the surface. The rake face 7 is a face that continues from the cutting edge 4 and is a face that continues to the chip discharge groove 5. The cutting edge 4 is formed between each chisel edge corner 8 a at both ends of the chisel edge 8 and each outer peripheral corner 9 on the circumference corresponding to the circumference of the conical bottom surface of the conical tip 2. A space 5a serving as an opening on the tip end side of the chip discharge groove 5 is formed at a front portion of the cutting blade 4 with respect to the rotation direction of the drill 1 (rotation counterclockwise in FIG. 1). Margins 10 are formed in the rear portions of each outer peripheral corner 9 with respect to the rotation direction of the drill 1, and are formed in a spiral shape on the outer peripheral surface 3 a of the body 3 of the drill 1 up to the base of the drill 1. . In addition, a pair of second numbering surfaces 13 having a smaller outer diameter of the tip end portion 2 by the dimension of the second numbering depth than that of the margin 10 part are provided in the rear part from each margin 10 with respect to the rotation direction of the drill 1. Thus formed, the outer peripheral surface 3 a of the body portion 3 of the drill 1 is spirally formed to the base portion of the drill 1. In addition, the line of intersection between each second picking surface 13 and each chip discharge groove 5 located rearward with respect to the rotation direction of the drill 1 is referred to as a heel 12. An intersection line between the margin 10 and the chip discharge groove 5 is referred to as a leading edge 11. Further, the leading edge 11 to the heel 12 are referred to as a land. For example, if each configuration is an embodiment of the twist drill 1 shown in FIG. 1, the twist drill 1 is viewed from the distal end portion 2 side in the axial direction of the rotation axis Qr, and the rotation axis Qr of the drill 1 is set. Each is formed at a rotationally symmetric position of 180 degrees around the center of rotation.

  From here, the structure of the drill 1 peculiar to this invention is demonstrated. In the drill 1 of the present invention, the intersecting line 4 forming the cutting edge 4 formed on the surface of the flank 6 has a shape in which two or more concave curve portions 15 that are concave in the rotation direction of the drill 1 are continuously arranged. And having one or more convex portions 16 formed by directly connecting the ends of the concave curve portions 15 adjacent to each other so as to be convex in the rotation direction of the drill 1, on the rake face 7 continuing from the cutting edge 4 Continuing from the concave curve portions 15 of the intersecting line 4 forming the cutting edge 4, the concave curved cross-section grooves 17 having a concave cross section and the same linear direction, preferably parallel to the axial direction of the rotation axis Qr, are formed side by side. It consists of

  For example, in the embodiment of the twist drill 1 shown in FIG. 1 to FIG. 4, each cutting edge 4 formed between the chisel edge corner 8 a and the outer periphery corner 9 is formed on the surface of the flank 6. The intersecting line 4 forming the cutting edge 4 has a shape in which three identical concave curve portions 15 (15a, 15b, 15c) that are recessed in the rotation direction of the drill 1 are continuously arranged, and adjacent concave curve portions 15a The same two convex portions 16 (16a, 16b) projecting in the direction of rotation of the drill into the portion formed by directly connecting the ends of 15b, the portion formed by directly connecting the ends of the adjacent concave curve portions 15b and 15c, and the most drill 1 Is formed in a shape having one convex portion 16 (16c) protruding in the rotation direction of the drill 1 at a portion formed by directly connecting the end of the concave curve portion 15c formed on the outer periphery of the drill 1 and the outer peripheral corner 9 of the drill 1. The convex portion 16 of the cutting edge 4 can reduce cutting resistance when cutting the workpiece, increase the cutting speed, shorten the cutting time, and further, the cutting edge 4. Can also be suppressed.

  Three concave curve portions 15 a, 15 b, 15 c and three convex portions 16 a, 16 b, 16 c formed on each cutting edge 4 are formed on the cutting edge 4 on at least a part of the rake face 7 that continues from the cutting edge 4. Three concave curve cross-section grooves 17 (17a, 17b, 17c) are machined in a direction parallel to the axial direction of the rotation axis Qr, with the same concave curve in cross section, starting from three identical concave curve portions 15a, 15b, 15c. It is formed by that. These concave curved cross-section grooves 17a, 17b, and 17c are formed by, for example, rotating an end mill having a diameter larger than a linear distance between both ends forming a concave curved section in a circle around an axis parallel to the rotation axis Qr of the drill 1. Since the wedge 14 comprising the cutting edge 4, the rake face 7 and the flank face 6 can be formed simply by cutting a groove having a circular cross section, the machining is very easy. Therefore, the drill 1 of the present invention can be applied even to a drill 1 having a very small diameter such as 0.5 mm or less. Note that the material of the cutting edge of the cutting tool such as an end mill for cutting the cutting edge 4 of the drill 1 corresponds to the material of the cutting edge 4 of the drill 1, high-speed tool steel, cemented carbide, polycrystalline cubic crystal. It is preferable to select a high hardness material having higher wear resistance than the cutting edge 4 of the drill 1 such as silicon nitride (PcBN) and polycrystalline sintered diamond (PCD).

  Therefore, as shown in FIG. 3, the drill 1 of the present invention has inner peripheral surfaces 170a, 170b of a plurality of concave curved cross-section grooves 17a, 17b, 17c formed in the same linear direction of the rake face 7. , 170c are formed so that the rake angles θa1, θb1, and θc1 are the same from the chisel edge corner 8a toward the outer peripheral corner 9 (θa1 = θb1 = θc1), and preferably a plurality of concave curved cross-sectional grooves 17a , 17b, 17c are formed in a direction parallel to the rotation axis Qr of the drill 1, and rake angles θa1, θb1, θc1 from the chisel edge corner 8a to the outer corner 9 are formed. Is formed to be zero (θa1 = θb1 = θc1 = zero). Further, as shown in FIG. 4, the drill 1 of the present invention has a ridge line 18 (18a) between adjacent concave curved cross-sectional grooves 17 (between 17a and 17b and 17b and 17c) of the rake face 7. 18b) and the ridge line 19 between the outermost concave curved cross-section groove 17c and the leading edge 11 so that the rake angles θa2, θb2, and θc2 gradually increase from the chisel edge corner 8a toward the outer peripheral corner 9. (Θa2 <θb2 <θc2), and the inner peripheral surfaces 170a, 170b, 170c of the plurality of concave curved cross-section grooves 17a, 17b, 17c are formed in a direction parallel to the rotation axis Qr of the drill 1. The rigidity of the cutting edge 4 can also be increased. Here, the rake angles θa1, θb1, θc1, θa2, θb2, and θc2 are set such that the angle of the axis parallel to the rotation axis Qr is zero, and the axis parallel to the rotation axis Qr and a predetermined position of the rake face 7 The angle between.

  Therefore, in the drill 1 of the present invention, the rake angles θa1, θb1, and θc1 are substantially equal in the most range of the cutting edge 4 from the chisel edge corner 8a side to the outer peripheral corner 9 side. By being parallel to the axial direction of the rotation axis Qr, the rake face 7 is not twisted, and the direction perpendicular to the cutting edge 4 at each position on the cutting edge 4 by the plurality of concave curved portions 15 of the cutting edge 4 is further improved. If the material of the workpiece is titanium, for example, if the material of the work piece is titanium, the outflow angle is eliminated by being different depending on the position, and the discharge angle is eliminated, so that the chip is shown in FIG. As shown in FIG. 5, the zigzag-shaped chip 20 in which the cross-section in the continuous direction of the chips 20 is folded. For example, if the material of the workpiece is aluminum, the chip 20 shown in FIG. It is formed into a zigzag-shaped or straight-shaped chip 20 according to the type of material of the workpiece so that it becomes such a straight-shaped chip 20, and is perpendicular to the direction in which the chips 20 continue. The cross-section is a chip 20 having a shape having concave curve portions 21a, 21b, 21c formed by the concave curve portion 15 of the cutting edge 4 and convex portions 22a, 22b, 22c formed by the convex portion 16 of the cutting edge 4. Thus, the paper is discharged without being curled sideways or upward. The chips 20 discharged during the cutting process by the drill 1 of the present invention are in particular in the chip discharge grooves 5 depending on the shapes of the concave curved portions 21a, 21b, 21c and the convex portions 22a, 22b, 22c of the chips 20. When the external force is applied, the shape is easily cut or broken at an appropriate location. For example, when the external force is applied from a direction substantially perpendicular to the continuous direction of the chips 20, the chip discharge groove 5, while ensuring an appropriate gap, the chip 20 is cut into pieces that are surely discharged to the outside of the chip discharge groove 5. Further, even when the chip 20 having such a shape is to be wound around the drill 1, the chip 20 is broken and divided before that, so that the chip 20 is wound around the drill 1 to break the drill 1. Can also be prevented.

  In the drill 1 of the present invention, the distance between both end portions of the concave curve portion 15 formed on the cutting edge 4, the shape of the concave curve portion 15, and the shape of the concave curve cross-sectional groove 17 are limited to the above-described embodiments. Without limitation, the shape and size of each concave curve portion 15 and each concave curve cross-sectional groove 17 to be provided may be different, or the shape and size may be the same, Those having the same or different shapes and dimensions may be appropriately combined. The drill 1 of the present invention is not limited to a twist drill, but can be applied to a drill having at least one cutting edge 4.

  INDUSTRIAL APPLICABILITY The present invention can be used for a drill that is a tool for making a hole in the rotation axis direction of a tool that rotates with respect to a workpiece.

DESCRIPTION OF SYMBOLS 1 Drill 2 Front-end | tip part 2a End surface 3 of the front-end | tip body 3a 3a Outer peripheral surface of a trunk | drum 4 Cutting edge (intersection line between flank and rake face)
5 Chip Discharge Groove 5a Space for Opening on the Tip Side of Chip Discharge Groove 6 Escape Surface 7 Rake Face 8 Chisel Edge 8a Chisel Edge Corner 9 Outer Corner Corner 10 Margin 11 Leading Edge 12 Heel 13 Die Cutting Surface 14 Wedge 15 Cutting Edge Concave curve portion 15a, 15b, 15c Concave curve portion 16 of cutting edge Convex portion 16a, 16b, 16c of cutting edge Convex portion 17 of cutting edge Concave cross section groove 17a, 17b, 17c Concave cross section groove 18 Concave cross section grooves Ridge lines 18a, 18b between the concave curve cross-section grooves 19 Ridge lines 19 between the outermost concave curve cross-section grooves and the leading edge Chips 21a, 21b, 21c Chip concave curve sections 22a, 22b , 22c Chip convex portions 170a, 170b, 170c Inner peripheral surface Qr of concave curved cross-sectional groove Drill rotation axis

Claims (3)

By rotating around the axis and moving forward in the axial direction, the workpiece is cut with a cutting edge at the tip, and the chips are discharged from the chip discharge groove at the barrel, and the workpiece A drill for drilling an object in the axial direction,
The cutting edge is formed by a line of intersection between a flank formed by the end face of the tip and a rake face following the chip discharge groove, and the line of intersection on the flank is concave in the direction of rotation. Two or more parts are continuously arranged, and the shape has one or more convex parts formed by directly connecting the ends of adjacent concave curved parts that are convex in the direction of rotation. A drill formed by arranging, on the rake face that continues from the intersection line, the concave curve cross-sectional grooves that are concave and have the same cross-section in the same straight line from the concave curve portions of the intersection line.   The drill according to claim 1, wherein the concave curved cross-sectional grooves in a direction parallel to the axial direction of the rotating shaft are formed side by side.   3. The drill according to claim 1, wherein each of the concave curved cross-section grooves is processed by a cutting tool made of polycrystalline sintered diamond (PCD).

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