JP2012035397A - Drill - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a drill from being partially lost or broken and to make high accuracy attainable in drilling, by suppressing generation of continuous chips without being affected by machining conditions in a drill.SOLUTION: The drill is configured to form a conically shaped blade part 12 in the tip end of a columnar drill body 11. The blade part 12 includes: a plurality of cutting edges 21a, 21b formed with prescribed spaces apart in the circumferential direction; a plurality of flanks 22a, 22b formed rearward in the rotating direction of the cutting edges 21a, 21b; and a plurality of discharge grooves 23a, 23b formed rearward in the rotating direction of each of the flanks 22a, 22b. In each cutting edges 21a, 21b, the shape in the feeding direction is made different from each other.

Description

  The present invention relates to a drill for drilling a workpiece.

  In general drills, cutting edges facing each other are formed at the tip of a drill body having a deformed cross section connected to a cylindrical shank, and a slope serving as a flank is formed at the rear in the rotation direction connected to the cutting edge. A guide surface extending rearward in the axial direction from the edge of the slope is formed. The cutting edge is set with a constant cutting edge angle that recedes toward the rear end side as it goes radially outward from the axial center of the front end portion. In such a drill, if chips that are continuously discharged get entangled with the drill, the drill may be broken or broken, or the work surface may be damaged.

  As a drill for solving such a problem, there is a drill described in Patent Document 1 below. The drill described in Patent Document 1 forms a stepped portion having a stepped guide surface extending in the axial direction and a stepped end surface extending in the radial direction at the outer peripheral corner of the tip cutting edge. A stepped cutting edge is formed on the intersection ridgeline between the end face of the groove and the side surface of the groove where the chip discharge groove is erected, and the tip of the pressing portion located in the front of the chip discharge groove in the rotation direction is moved backward in the axial direction from the step cutting edge. It is something that was positioned.

Japanese Patent Laid-Open No. 11-138320

  In the conventional drill described above, the tip cutting edge and the step cutting edge are arranged at a position sharing the chip discharge groove, so that the chips discharged by the step cutting edge can be discharged smoothly without retaining. It becomes. That is, in this conventional drill, the chips that are continuously discharged during the drilling process are bent halfway by the end face of the step portion, thereby suppressing the occurrence of continuous chips. However, in this case, unless the feed amount at the time of drilling with a drill is large to some extent, it becomes difficult to properly fold the chips to be discharged at the end surface of the stepped portion. When the feed amount of the drill is large, a large load is applied to the drill or the motor, and the work surface of the work cannot be improved, and the work may be deformed.

  The present invention solves the above-described problems, and suppresses the generation of continuous chips regardless of machining conditions, thereby preventing drill breakage and breakage and increasing the accuracy of drilling. The purpose is to provide a drill.

  In order to achieve the above object, a drill according to the present invention is a drill in which a conical blade portion is formed at the tip of a cylindrical drill body, and the blade portions are arranged at predetermined intervals in the circumferential direction. A plurality of cutting edges formed, a plurality of flank surfaces formed rearward in the rotational direction of the respective cutting edges, and a plurality of discharge grooves formed rearward in the rotational direction of the respective flank faces, The shape in the feed direction is different for each cutting edge.

  Therefore, when drilling a workpiece, by rotating the drill body and setting a predetermined feed amount, each cutting edge in the blade part sequentially scrapes the surface of the workpiece, but for each cutting edge Since the shape in the feed direction is different, the shape of the chip is different for each cutting edge and becomes intermittent, and as a result, it is possible to suppress the occurrence of continuous chips regardless of the processing conditions. In addition, it is possible to prevent drill breakage and breakage and to increase the accuracy of drilling.

  In the drill according to the present invention, a groove is formed in the blade from the cutting edge to the flank, and a radial position in the groove is different for each cutting edge.

  Therefore, by rotating the drill body and setting a predetermined feed amount, when each cutting edge in the blade part scrapes the surface of the workpiece in order, the radial position in the groove part formed from the cutting edge to the flank is Since it differs for each cutting edge, the chip width is different for each cutting edge and becomes intermittent, and by suppressing the occurrence of continuous chips, drill breakage and breakage are prevented. It is possible to increase the accuracy of drilling.

  In the drill of the present invention, the groove portion is characterized in that the width increases toward the rear in the rotation direction.

  Therefore, when the width of the groove portion is widened, an acute angle portion is formed on both sides of the cutting edge and a flank surface is formed, and this cutting accuracy can be improved and the contact between the flank surface and the workpiece surface can be improved. Can be prevented.

  In the drill according to the present invention, each of the cutting edges has a corrugated shape in the feeding direction, and the radial position of the unevenness is different for each of the cutting edges.

  Accordingly, by rotating the drill body and setting a predetermined feed amount, when each cutting edge in the blade portion sequentially scrapes the surface of the workpiece, each cutting edge forms a wave shape and the radial position on the unevenness is Since it differs for each cutting edge, the chip width is different for each cutting edge and becomes intermittent, and by suppressing the occurrence of continuous chips, drill breakage and breakage are prevented. It is possible to increase the accuracy of drilling.

  According to the drill of the present invention, a plurality of cutting edges are formed at predetermined intervals in the circumferential direction as the blade portion, and the shape in the feed direction is different for each cutting edge. By suppressing the occurrence of drilling, it is possible to prevent drill breakage and breakage and to increase the accuracy of drilling.

FIG. 1 is a schematic side view of a drill according to Embodiment 1 of the present invention. FIG. 2 is a schematic front view of the drill of the first embodiment. FIG. 3A is a schematic diagram illustrating drilling by a drill according to the first embodiment. FIG. 3-2 is a schematic diagram illustrating a drilling process using the drill according to the first embodiment. FIG. 3C is a schematic diagram illustrating a drilling process using the drill according to the first embodiment. FIGS. 3-4 is the schematic showing the drilling process by the drill of Example 1. FIGS. 3-5 is a schematic diagram illustrating a drilling process using a drill according to Example 1. FIG. FIG. 4 is a schematic front view of a drill according to Embodiment 2 of the present invention. FIG. 5 is a schematic side view of a drill according to Embodiment 3 of the present invention.

  Exemplary embodiments of a drill and a rotating machine according to the present invention will be described below in detail with reference to the accompanying drawings. In addition, this invention is not limited by this Example, Moreover, when there exists multiple Example, what comprises combining each Example is also included.

  1 is a schematic side view of a drill according to a first embodiment of the present invention, FIG. 2 is a schematic front view of the drill of the first embodiment, and FIGS. 3-1 to 3-5 are drilling holes by the drill of the first embodiment. It is the schematic showing processing.

  In the drill of the first embodiment, as shown in FIGS. 1 and 2, the drill body 11 has a cylindrical shape, a shank portion (not shown) is formed at one end portion, and a part of a circle is cut out in a fan shape at the other end portion. A blade portion 12 having a conical shape is formed. The blade portion 12 includes a plurality (two in this embodiment) of cutting edges 21a and 21b formed at a predetermined interval (180 degrees in the present embodiment) in the circumferential direction, and each of the cutting blades 21a, 21a, A plurality (two in this embodiment) of flank surfaces 22a and 22b formed at the rear of the rotational direction R in 21b, and a plurality (this embodiment) of the flank surfaces 22a and 22b formed at the rear of the rotational direction R. In the example, there are two) discharge grooves 23a and 23b.

  The cutting edges 21 a and 21 b have a predetermined angle α (hereinafter referred to as “tip angle α”) in a direction from the tip to the outer peripheral side following the chisel portion 24 including the axis O to the outer periphery of the blade portion 12. It is extended. Although not shown, the blade portion 12 is formed with a groove (hereinafter referred to as “thinning”) adjacent to the cutting edges 21a and 21b in the vicinity of the center side of the cutting edges 21a and 21b. This thinning enables the cutting action to be performed in the vicinity of the center side where the cutting speed is low, the pushing force in the axial direction of the drill main body 11 is reduced, and centripetality, biting property, and positioning accuracy are improved. It becomes possible.

  The flank surfaces 22a and 22b are positioned rearward in the rotational direction R of the cutting edges 21a and 21b, and are formed so as to be inclined rearward in the axial direction as going outward in the radial direction. Further, outer flank flank surfaces 25a and 25b extending along the central axis line are formed continuously with the flank surfaces 22a and 22b and positioned rearward in the axial direction of the drill body 11. By forming the clearance surfaces 22a and 22b and the outer peripheral clearance surfaces 25a and 25b, portions other than the cutting edges 21a and 21b are prevented from interfering with the inner wall surface of the processing hole during processing.

  The discharge grooves 23 a and 23 b are located on the outer peripheral portion of the blade portion 12 for discharging chips, and are formed along the direction of the central axis of the drill body 11. Since the discharge grooves 23a and 23b are formed deep and wide, chips generated during machining are smoothly discharged from the front end side to the rear end side of the drill body 11 through the discharge grooves 23a and 23b. be able to.

  In the drill of Example 1 configured as described above, the cutting edges 21a and 21b constituting the blade portion 12 have different shapes in the feed direction for the respective cutting edges 21a and 21b. Specifically, groove portions 26a and 26b are formed in the blade portion 12 from the cutting blades 21a and 21b to the relief surfaces 22a and 22b, and the radial positions in the groove portions 26a and 26b are different for each cutting blade 21a and 21b. Yes.

  That is, one cutting edge 21a has a predetermined blade width W from the chisel portion 24 to the outer peripheral portion, and two groove portions 26a are formed at an interval of W / 3 from the cutting edge 21a to the flank 22a. The other cutting edge 21b has a predetermined blade width W from the chisel portion 24 to the outer peripheral portion, and one groove portion 26b is formed from the cutting edge 21b to the flank 22b at intervals of W / 2. In this case, the widths and depths of the grooves 26a and 26b are set to substantially the same dimensions. Each of the groove portions 26 a and 26 b may be formed in an arc shape centered on the axis O of the drill body 11.

  Here, the drilling process by the drill of Example 1 is demonstrated.

  When the drill body 11 is rotated in the R direction (see FIG. 2) at a predetermined number of revolutions and the drill body 11 is advanced in the axis O direction (see FIG. 1) with a predetermined feed amount, Drilling can be performed by cutting the surface of the workpiece 101 (see FIG. 3A) in order by the blades 21a and 21b. In this case, the feed amount per half rotation of the drill body 11 needs to be set smaller than the depth of each groove 26a, 26b.

  At this time, as shown in FIGS. 1 and 3-1, when the cutting edge 21a scrapes off the surface 102 of the workpiece 101, the two convex portions 103 corresponding to the two groove portions 26a are formed on the surface 102 in the rotational direction of the drill body 11. Formed along R. Subsequently, as shown in FIG. 3-2, when the cutting edge 21 b scrapes off the surface 102 of the workpiece 101 having the two convex portions 103, one convex portion 104 corresponding to one groove portion 26 b is drilled on the surface 102. It is formed along the rotation direction of the main body 11. At this time, as shown in FIG. 3C, the generated chip 111 is divided into two in the width direction by the groove 26b, and the width becomes narrow.

  Then, as shown in FIG. 3-4, when the cutting edge 21 a scrapes off the surface 102 of the workpiece 101 having one convex portion 104, two convex portions 103 corresponding to the two groove portions 26 a are formed on the surface 102. Is formed along the rotation direction of the drill body 11. At this time, as shown in FIG. 3-5, the generated chip 112 is divided into three in the width direction by the groove 26a, and the width becomes narrow.

  As described above, when the drill body 11 is rotated and drilling is performed, the radial positions of the groove portions 26a and 26b formed for the respective cutting blades 21a and 21b in the blade portion 12 are different. , 21b, the chip width is different, and it becomes easy to break. Therefore, when the generated chips are discharged from the discharge grooves 23a and 23b, the roots, that is, the positions of the cutting edges 21a and 21b are periodically broken due to vibrations or the like, and the chips are intermittently discharged. Therefore, the generation of continuous chips is suppressed.

  Thus, in the drill of Example 1, the conical blade portion 12 is formed at the tip of the cylindrical drill body 11, and the blade portion 12 is formed at predetermined intervals in the circumferential direction. The plurality of cutting edges 21a, 21b, the plurality of flank surfaces 22a, 22b formed at the rear in the rotation direction of the cutting edges 21a, 21b, and the plurality of the flank surfaces 22a, 22b formed at the rear in the rotation direction. The discharge grooves 23a and 23b are provided, and the shape in the feed direction is made different for each of the cutting edges 21a and 21b.

  Therefore, when drilling a workpiece, by rotating the drill body 11 and setting a predetermined feed amount, each of the cutting edges 21a and 21b in the blade portion 12 scrapes the surface of the workpiece in order. Since the shape in the feeding direction is different for each cutting edge 21a, 21b, the shape of the chip is different for each cutting edge 21a, 21b, and as a result, it is not affected by the processing conditions. By suppressing the generation of continuous chips, it is possible to prevent drill breakage and breakage and to increase the accuracy of drilling.

  Specifically, groove portions 26a and 26b are formed in the blade portion 12 from the cutting blades 21a and 21b to the relief surfaces 22a and 22b, and the radial positions in the groove portions 26a and 26b are made different for the respective cutting blades 21a and 21b. Yes. Therefore, it becomes easy to bend because the width of the chip is different for each of the cutting edges 21a and 21b, and the occurrence of continuous chips is suppressed, thereby preventing the drill from being broken or broken and improving the accuracy of the drilling process. Can be made possible.

  FIG. 4 is a schematic front view of a drill according to Embodiment 2 of the present invention. In addition, the same code | symbol is attached | subjected to the member which has the function similar to the Example mentioned above, and detailed description is abbreviate | omitted.

  In the drill of the second embodiment, as shown in FIG. 4, a blade portion 12 is formed at the tip of the drill body 11, and the blade portion 12 includes two cutting edges 21 a and 21 b and two flank surfaces 22 a and 22 b. It has two discharge grooves 23a and 23b. And the groove part 31a, 31b is formed in the blade part 12 from the cutting blade 21a, 21b to the flank 22a, 22b, and the radial direction position in this groove part 31a, 31b differs for each cutting edge 21a, 21b. Further, the groove portions 31a and 31b are formed so that the width thereof becomes wider toward the rear in the rotation direction.

  That is, one cutting edge 21a is formed with two groove portions 31a at equal intervals in the width direction (the radial direction of the drill body 11), and the other cutting edge 21b is formed in the width direction (the radial direction of the drill body 11). One groove portion 31b is formed at the center position. And each groove part 31a, 31b is formed in the shape where the width | variety becomes wide toward the back of the rotation direction R of the drill main body 11. As shown in FIG. Therefore, the corners of the cutting edges 21a and 21b become acute angles by the grooves 31a and 31b, and high-precision cutting is possible. Further, since the corners of the cutting edges 21a and 21b are acute, flank surfaces are formed on both sides of the respective groove portions 31a and 31b so as to be separated from the workpiece toward the rear in the rotation direction R of the drill main body 11. Contact between 31a and 31b and the workpiece is suppressed.

  In addition, since the drilling process by the drill of Example 2 is substantially the same as Example 1 mentioned above, description is abbreviate | omitted.

  As described above, in the drill according to the second embodiment, the blade portion 12 is provided with the plurality of cutting blades 21a and 21b, the flank surfaces 22a and 22b, and the discharge grooves 23a and 23b, and the blade portion 12 includes the cutting blades 21a and 21b. Groove portions 31a and 31b are formed over the flank surfaces 22a and 22b, and the radial positions of the groove portions 31a and 31b are made different for the respective cutting edges 21a and 21b. It is formed so that its width becomes wider.

  Accordingly, by increasing the width of the groove portions 31a and 31b, acute angle portions are formed on both sides of the cutting edges 21a and 21b, and flank surfaces are formed, so that the cutting surface can be processed with high accuracy, Cutting accuracy can be improved, contact between the flank surfaces of the grooves 31a and 31b and the workpiece surface can be prevented, and high accuracy in drilling can be achieved.

  FIG. 5 is a schematic side view of a drill according to Embodiment 3 of the present invention. In addition, the same code | symbol is attached | subjected to the member which has the function similar to the Example mentioned above, and detailed description is abbreviate | omitted.

  In the drill of the third embodiment, as shown in FIG. 5, a blade portion 41 is formed at the tip of the drill body 11, and the blade portion 41 includes two cutting blades 42a and 42b and two flank surfaces 22a and 22b. It has two discharge grooves 23a and 23b. And each cutting edge 42a, 42b comprises the waveform which makes an unevenness | corrugation in a feed direction, and the radial direction position in an unevenness | corrugation differs for each cutting edge 42a, 42b.

  That is, the one cutting edge 42a has a concave shape at the center in the width direction (the radial direction of the drill body 11), and has convex shapes on both sides. The other cutting edge 42b has a convex shape at the center in the width direction (the radial direction of the drill body 11) and a concave shape on both sides thereof.

  Accordingly, when the drill main body 11 is rotated at a predetermined number of revolutions and the drill main body 11 is advanced with a predetermined feed amount, the cutting edges 42a and 42b in the blade portion 41 sequentially scrape off the surface of the workpiece, thereby drilling. It can be performed. In this case, the feed amount per half rotation of the drill body 11 needs to be set to be smaller than the uneven depth of the cutting edges 42a and 42b.

  At this time, if the cutting edges 42a and 42b scrape off the surface of the workpiece in order, the generated chips are easily broken because their widths and numbers are different. Therefore, when the generated chips are discharged from the discharge grooves 23a and 23b, the roots, that is, the positions of the cutting edges 42a and 42b are periodically broken due to vibration or the like, and chip discharge is intermittent. Therefore, the generation of continuous chips is suppressed.

  As described above, in the drill of the third embodiment, as the blade portion 41, a plurality of cutting blades 42a and 42b, relief surfaces 22a and 22b, and discharge grooves 23a and 23b are provided. The corrugated shape is uneven in the feed direction, and the radial position of the unevenness is different for each of the cutting edges 42a and 42b.

  Therefore, when drilling a workpiece, by rotating the drill body 11 and setting a predetermined feed amount, each of the cutting edges 42a and 42b in the blade portion 41 sequentially scrapes the surface of the workpiece. Since the uneven shape in the feed direction is different for each cutting edge 42a, 42b, the shape of the chip is different for each cutting edge 42a, 42b and is intermittent, and as a result, it is not affected by the processing conditions. By suppressing the occurrence of continuous chips, it is possible to prevent drill breakage and breakage and to increase the accuracy of drilling.

  In each of the above-described embodiments, the cutting edges 21a, 21b, 42a, 42b, the flank surfaces 22a, 22b, and the discharge grooves 23a, 23b are each two, but may be three or more. Moreover, although the shape of the cutting blades 21a, 21b, 42a, and 42b is provided with the groove portions 26a, 26b, 31a, and 31b, or a wave shape, it is not limited to these shapes, and a plurality of cutting blades are provided. As long as the shape in the feeding direction is different, any shape may be used.

  The drill according to the present invention prevents the chipping and breakage of the drill by making the shape in the feed direction different for each of the plurality of cutting edges, thereby suppressing the occurrence of continuous chips regardless of the processing conditions. At the same time, the drilling process can be made highly accurate, and can be applied to any type of drill.

11 Drill body 12, 41 Blade part 21a, 21b, 42a, 42b Cutting edge 22a, 22b Flank 23a, 23b Discharge groove 26a, 26b, 31a, 31b Groove part

Claims (4)

A drill in which a conical blade portion is formed at the tip of a cylindrical drill body,
The blade portion is
A plurality of cutting edges formed at predetermined intervals in the circumferential direction;
A plurality of flank surfaces formed at the rear of the cutting edge in the rotational direction;
A plurality of discharge grooves formed at the rear of the flank in the rotational direction;
Have
The shape of the feed direction is different for each cutting edge,
A drill characterized by that.   The drill according to claim 1, wherein a groove is formed in the blade from the cutting edge to the flank, and a radial position in the groove is different for each cutting edge.   The drill according to claim 2, wherein the groove portion has a width that increases toward the rear in the rotation direction.   2. The drill according to claim 1, wherein each of the cutting edges has a wave shape that is uneven in a feeding direction, and a radial position of the unevenness is different for each of the cutting edges.

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