JP2014193513A - Drill - Google Patents

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JP2014193513A
JP2014193513A JP2013071102A JP2013071102A JP2014193513A JP 2014193513 A JP2014193513 A JP 2014193513A JP 2013071102 A JP2013071102 A JP 2013071102A JP 2013071102 A JP2013071102 A JP 2013071102A JP 2014193513 A JP2014193513 A JP 2014193513A
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cutting edge
thinning
drill
main cutting
honing
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Koichiro Naruge
康一郎 成毛
Sohei Takahashi
宗平 高橋
Chuichi Ohashi
忠一 大橋
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Mitsubishi Materials Corp
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Mitsubishi Materials Corp
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Abstract

PROBLEM TO BE SOLVED: To suppress the increase of cutting resistance in a thinning edge while preventing damage or the like by securing a cutting edge strength in a connection part of the thinning edge and a main cutting edge.SOLUTION: A cutting edge 4 formed at the top of a drill body 1 rotated around an axis line O is provided with a main cutting edge 4A extending from an outer peripheral end to an inner peripheral side, and a thinning edge 4B. The thinning edge 4B is connected to the main cutting edge 4A through a connection part 4C which is formed in a projecting curve shape contacting the main cutting edge 4A or in a projectingly curved broken line shape comprising a plurality of straight lines in view of the top side of an axis line O direction. Further, horning is applied to at least the connection part 4C side of the main cutting edge 4A to form a horning face 7. The horning angle of the horning face 7 is equalized to the rake angle of the thinning edge 4B by the thinning face 6A and thereby, the horning face 7 smoothly continues to the thinning face 6A.

Description

本発明は、主切刃の内周に連なるシンニング刃が形成された切刃を有するドリルに関するものである。   The present invention relates to a drill having a cutting blade in which a thinning blade connected to the inner periphery of a main cutting blade is formed.

このようなシンニング刃を有するドリルとして、例えば特許文献1には、ドリル本体の先端部に、逃げ面側にあるシンニングによって先端切刃稜(主切刃)に連続するチゼルエッジが構成され、チゼルエッジのシンニング側には幅狭の面取り部分が形成されるとともに、先端切刃稜は、芯厚部分では、チゼルエッジを構成するシンニング垂面に対し、円弧面または平面からなる接続面が介在することにより、小円弧稜または小直線稜が形成されるようになっていて、これら小円弧稜または小直線稜を含めた全稜線に、上記面取部分と連続するホーニング処理が施されたものが提案されている。   As a drill having such a thinning blade, for example, in Patent Document 1, a chisel edge that is continuous with a tip cutting edge ridge (main cutting edge) by a thinning on the flank side is formed at the tip of a drill body. A narrow chamfered portion is formed on the thinning side, and the tip cutting edge ridge has a connecting surface consisting of an arc surface or a plane on the thinning vertical surface constituting the chisel edge at the core thickness portion, Small arc ridges or small straight ridges are formed, and all ridge lines including these small arc ridges or small straight ridges have been subjected to honing processing that is continuous with the chamfered portion. Yes.

また、特許文献2には、ドリル本体先端の外周部側において先端逃げ面と切屑排出溝とによって直線状の第1切刃(主切刃)が形成されるとともに、この第1切刃より中心部側にシンニング面が形成されて、このシンニング面と先端逃げ面とによって第2切刃(シンニング刃)が形成され、第1切刃の垂直方向すくい角が小さくなるようにして、第1切刃に対する切屑排出溝のすくい面に、外周に向けて広がったギャッシュ面が形成されたものが提案されており、このギャッシュ面は略三角形状とされている。   Further, in Patent Document 2, a linear first cutting edge (main cutting edge) is formed by a tip flank and a chip discharge groove on the outer peripheral side of the tip of the drill body, and more central than the first cutting edge. A thinning surface is formed on the part side, and a second cutting edge (thinning blade) is formed by the thinning surface and the tip flank, and the first rake angle of the first cutting edge is reduced to reduce the first cutting edge. It has been proposed that a rake face of the chip discharge groove with respect to the blade is formed with a gash surface extending toward the outer periphery, and the gash face has a substantially triangular shape.

特開平4−25308号公報JP-A-4-25308 特開2005−186247号公報JP 2005-186247 A

しかしながら、特許文献1に記載のドリルでは、チゼルエッジのシンニング側から小円弧稜または小直線稜を含めた先端切刃稜までの全稜線に、面取り部分が形成されるとともにおよびホーニングが施されているため、切刃強度は向上するものの、特にシンニング側で切削抵抗が大きくなってしまい、シンニングを施しているにも関わらず、スラスト荷重の増大を招くことになる。   However, in the drill described in Patent Document 1, a chamfered portion is formed and honed on all ridge lines from the thinning side of the chisel edge to the tip cutting edge ridge including the small arc ridge or the small straight ridge. Therefore, although the cutting edge strength is improved, the cutting resistance is increased particularly on the thinning side, and the thrust load is increased in spite of the thinning.

一方、特許文献2に記載のドリルでは、ギャッシュ面が三角形状であって、シンニング面とは1点で接するか、シンニング面との間にギャッシュ面が形成されない部分が形成されて不連続となるため、特に特許文献2に記載されているように第1、第2切刃がともに直線状とされている場合には、これら第1、第2切刃が接続されるこの部分や上記1点で切刃強度が損なわれて欠損等が生じ易くなるおそれがある。このような問題は、特に切刃が形成される刃先部がダイヤモンド焼結体やcBN(立方晶窒化硼素)焼結体のような超高圧焼結体よりなる場合に、このような超高圧焼結体は超高硬度である反面、脆いので顕著となる。   On the other hand, in the drill described in Patent Document 2, the gash surface has a triangular shape and is in contact with the thinning surface at one point, or a portion where the gash surface is not formed is formed between the thinning surface and becomes discontinuous. For this reason, particularly when both the first and second cutting edges are linear as described in Patent Document 2, this portion to which the first and second cutting edges are connected and the above-mentioned one point Therefore, there is a possibility that the cutting edge strength is impaired and a defect or the like is likely to occur. Such a problem occurs particularly when the cutting edge where the cutting edge is formed is made of an ultra-high pressure sintered body such as a diamond sintered body or a cBN (cubic boron nitride) sintered body. The bonded body is extremely hard, but becomes noticeable because it is brittle.

本発明は、このような背景の下になされたもので、シンニング刃の主切刃との接続部における切刃強度を確保して欠損等を防ぎつつも、シンニング刃における切削抵抗の増大を抑制することが可能なドリルを提供することを目的としている。   The present invention has been made under such a background, and suppresses an increase in cutting resistance in the thinning blade while ensuring the cutting edge strength at the connection portion of the thinning blade with the main cutting edge to prevent chipping and the like. The aim is to provide a drill that can be.

上記課題を解決して、このような目的を達成するために、本発明は、軸線回りに回転されるドリル本体の先端部外周に切屑排出溝が形成され、この切屑排出溝のドリル回転方向を向く壁面と上記ドリル本体の先端逃げ面との交差稜線部に切刃が形成されたドリルであって、上記切刃は、該切刃の外周端から内周側に延びる主切刃と、上記切屑排出溝のドリル回転方向を向く壁面の内周部を上記軸線側に切り欠くように形成されたシンニング部のドリル回転方向を向くシンニング面と上記先端逃げ面との交差稜線部に形成されて上記主切刃の内周に連なるシンニング刃とを備え、このシンニング刃は、上記軸線方向先端側から見て上記主切刃に接する凸曲線状または複数の直線よりなる凸曲した折れ線状をなす接続部を介して該主切刃に接続されるとともに、上記主切刃の少なくとも上記接続部側にはホーニングが施されてホーニング面が形成されており、このホーニング面のホーニング角は上記シンニング面による上記シンニング刃のすくい角と等しくされていて、上記ホーニング面とシンニング面とが滑らかに連続していることを特徴とする。   In order to solve the above problems and achieve such an object, according to the present invention, a chip discharge groove is formed on the outer periphery of the tip of the drill body rotated about the axis, and the drill rotation direction of the chip discharge groove is changed. A drill in which a cutting edge is formed at an intersecting ridge line portion between a facing wall surface and a tip flank of the drill body, the cutting edge including a main cutting edge extending from an outer peripheral end of the cutting edge to an inner peripheral side, The inner peripheral part of the wall surface facing the drill rotation direction of the chip discharge groove is formed at the intersecting ridge line part of the thinning surface facing the drill rotation direction of the thinning part formed so as to cut out on the axis side and the tip flank surface. A thinning blade connected to the inner periphery of the main cutting edge, and the thinning blade has a convex curved line shape or a bent line shape formed by a plurality of straight lines in contact with the main cutting edge when viewed from the axial front end side. Connected to the main cutting edge via the connection In addition, honing is performed on at least the connection portion side of the main cutting blade to form a honing surface, and the honing angle of the honing surface is equal to the rake angle of the thinning blade by the thinning surface. The honing surface and the thinning surface are smoothly continuous.

従って、このように構成されたドリルにおいては、シンニング刃が、軸線方向先端側から見て主切刃に接する凸曲線状または複数の直線よりなる凸曲した折れ線状をなす接続部を介して主切刃と接続されていて、しかも主切刃の接続部側にはホーニングが施されているので、シンニング刃の接続部と主切刃とが連なる部分における切刃強度を確保することができて欠損等を防止することができる。   Therefore, in the drill configured in this way, the thinning blade is mainly connected via a connecting portion having a convex curve shape or a curved line shape composed of a plurality of straight lines in contact with the main cutting blade as viewed from the axial front end side. Since it is connected to the cutting edge and honing is applied to the connecting part side of the main cutting edge, it is possible to ensure the cutting edge strength at the part where the connecting part of the thinning blade and the main cutting edge are connected. Defects can be prevented.

そして、このホーニングによるホーニング面のホーニング角がシンニング刃のすくい角と等しくされていて、ホーニング面とシンニング面とが滑らかに連続していて、すなわち主切刃に施されたホーニングのホーニング面とシンニング刃の接続部に連なるシンニング面とが不連続となることがなく、たとえ切刃が形成される刃先部がダイヤモンド焼結体やcBN焼結体のような脆い超高圧焼結体であっても、欠損等を確実に防ぐことができる。その一方で、こうして切刃強度を確保しつつも、シンニング刃にはホーニングを施す必要がなくなるので、シンニング刃における切削抵抗が増大するのを抑えてスラスト荷重を確実に低減することが可能となる。   The honing angle of the honing surface by this honing is equal to the rake angle of the thinning blade, and the honing surface and the thinning surface are smoothly continuous, that is, the honing surface of the honing applied to the main cutting edge and the thinning Even if the cutting edge is formed with a brittle ultra-high pressure sintered body such as a diamond sintered body or a cBN sintered body, the thinning surface connected to the blade connecting portion is not discontinuous. It is possible to reliably prevent defects and the like. On the other hand, since it is no longer necessary to honing the thinning blade while ensuring the strength of the cutting blade in this way, it is possible to reliably reduce the thrust load by suppressing an increase in the cutting resistance in the thinning blade. .

ここで、上記軸線方向先端側から見て上記接続部がなす凸曲線の曲率半径または凸曲した折れ線に内接する円の半径は、上記切刃の外径Dに対して0.1×D以上とされるのが望ましい。この凸曲線の曲率半径または凸曲した折れ線に内接する円の半径が切刃の外径Dに対して0.1×Dを下回るほど小さいと接続部が尖った角部に近くなり、欠損等を十分に防ぐことができなくなるおそれが生じる。   Here, the radius of curvature of the convex curve formed by the connecting portion as viewed from the axial front end side or the radius of the circle inscribed in the convex bent line is 0.1 × D or more with respect to the outer diameter D of the cutting edge. It is desirable that If the radius of curvature of the convex curve or the radius of the circle inscribed in the convex bent line is smaller than 0.1 × D with respect to the outer diameter D of the cutting edge, the connection portion becomes close to a sharp corner, and the defect, etc. May not be sufficiently prevented.

また、主切刃の接続部側の欠損等を一層確実に防ぐには、この主切刃に形成される上記ホーニング面と上記先端逃げ面との交差稜線部に、断面凸曲線状の微小面取りが施されるのが望ましい。この微小面取りの断面がなす凸曲線の曲率半径は、例えば0.01mm〜0.02mm(10μm〜20μm)程度が望ましい。   Further, in order to more surely prevent chipping or the like on the connecting portion side of the main cutting edge, a minute chamfer having a convex curved cross section is formed at the intersecting ridge line portion between the honing surface and the tip flank formed on the main cutting edge. Is desirable. The radius of curvature of the convex curve formed by the micro-chamfered cross-section is preferably about 0.01 mm to 0.02 mm (10 μm to 20 μm), for example.

以上説明したように、本発明によれば、たとえ刃先部が超高圧焼結体により形成されていても、主切刃とシンニング刃との接続部やホーニング面とシンニング面が連続する部分における切刃強度を確保して欠損等を防止することができるとともに、シンニング刃における切削抵抗の増大を抑制してスラスト荷重の確実な低減を図ることができる。   As described above, according to the present invention, even if the cutting edge portion is formed of an ultra-high pressure sintered body, the connection portion between the main cutting edge and the thinning blade or the cutting portion at the portion where the honing surface and the thinning surface are continuous. The strength of the blade can be secured to prevent chipping and the like, and an increase in cutting resistance in the thinning blade can be suppressed to reliably reduce the thrust load.

本発明の一実施形態を示すドリル本体先端部の側面図である。It is a side view of a drill main part tip part showing one embodiment of the present invention. 図1に示すドリル本体先端部の一方の切刃を示す軸線方向先端側から見た正面図である。It is the front view seen from the axial direction front end side which shows one cutting blade of the drill main body front-end | tip part shown in FIG. 図1におけるZZ拡大断面図である。It is ZZ expanded sectional drawing in FIG.

図1ないし図3は、本発明の一実施形態を示すものである。本実施形態において、ドリル本体1は軸線Oを中心とした外形円柱状とされ、図示されない後端部がシャンク部とされて、このシャンク部が工作機械の主軸に把持されることにより軸線O回りにドリル回転方向Tに回転されつつ、該軸線O方向先端側(図1において上側)に送り出されて被削材に穴明け加工を行う。   1 to 3 show an embodiment of the present invention. In this embodiment, the drill body 1 has an outer cylindrical shape centered on the axis O, and a rear end portion (not shown) is a shank portion. The shank portion is gripped by the main shaft of the machine tool, thereby rotating around the axis O. While being rotated in the drill rotation direction T, the workpiece is sent to the tip side in the axis O direction (upper side in FIG. 1) to drill a work material.

なお、ドリル本体1は、その全体が超硬合金等の硬質材料によって一体に形成されたものでもよく、またドリル本体1先端部の後述する切刃が形成される刃先部がダイヤモンド焼結体やcBN焼結体のような超高圧焼結体によって形成されていて、それ以外の部分は超硬合金等の硬質材料によって形成されたものでもよい。   The drill body 1 may be integrally formed of a hard material such as a cemented carbide, and the tip of the drill body 1 at which the cutting edge described later is formed is a diamond sintered body or It may be formed of an ultra-high pressure sintered body such as a cBN sintered body, and the other parts may be formed of a hard material such as a cemented carbide.

ドリル本体1の先端部の外周には、このドリル本体1の先端面に開口して後端側に向かうに従い軸線O回りにドリル回転方向Tの後方側に捩れる切屑排出溝2が、本実施形態では軸線Oに関して180°回転対称に一対形成されており、これらの切屑排出溝2のドリル回転方向Tを向く壁面と、上記ドリル本体1先端面における切屑排出溝2の開口部からドリル回転方向T後方側に延びる先端逃げ面3との交差稜線部に切刃4がそれぞれ形成されている。すなわち、本実施形態のドリルは2枚刃のツイストドリルである。   On the outer periphery of the tip of the drill body 1, there is a chip discharge groove 2 that opens at the tip surface of the drill body 1 and twists toward the rear side in the drill rotation direction T around the axis O toward the rear end side. In the form, a pair is formed with rotational symmetry of 180 ° with respect to the axis O, the wall surface of the chip discharge groove 2 facing the drill rotation direction T, and the drill rotation direction from the opening of the chip discharge groove 2 on the tip end surface of the drill body 1. Cutting edges 4 are respectively formed at intersection ridges with the tip flank 3 extending to the T rear side. That is, the drill of this embodiment is a two-blade twist drill.

先端逃げ面3は、ドリル回転方向T後方側に向かうに従いドリル本体1の後端側に向かうように傾斜して切刃4に逃げ角が付されるとともに、ドリル本体1の先端部外周側に向けても後端側に向かうように傾斜して、切刃4に先端角が与えられるようにされている。なお、この先端逃げ面3には、本実施形態では、切刃4のドリル回転方向T後方に連なる第1逃げ面3Aと、この第1逃げ面3Aのさらにドリル回転方向T後方側に連なり、第1逃げ面3Aよりも大きな逃げ角が与えられた第2逃げ面3Bとが形成されている。   The tip flank 3 inclines toward the rear end side of the drill body 1 toward the rear side of the drill rotation direction T, gives a clearance angle to the cutting edge 4, and moves toward the outer peripheral side of the tip portion of the drill body 1. Even if it is directed, the cutting edge 4 is inclined so as to be directed toward the rear end side, and a tip angle is given to the cutting edge 4. In this embodiment, the tip flank 3 is connected to the first flank 3A continuous to the rear side of the drill rotation direction T of the cutting edge 4 and further to the rear side of the first flank 3A in the drill rotation direction T. A second flank 3B having a larger flank angle than the first flank 3A is formed.

さらに、ドリル本体1の先端部内には、周方向における一対の切屑排出溝2の間の部分に、これらの切屑排出溝2と等しいリードで捩れるクーラント穴5がそれぞれ形成されている。これらのクーラント穴5は、本実施形態ではドリル本体1の先端逃げ面3において上記第2逃げ面3Bに開口させられている。   Further, in the tip portion of the drill main body 1, coolant holes 5 that are twisted with leads equal to these chip discharge grooves 2 are formed at portions between the pair of chip discharge grooves 2 in the circumferential direction. In the present embodiment, these coolant holes 5 are opened to the second flank 3 </ b> B at the tip flank 3 of the drill body 1.

また、切屑排出溝2のドリル本体1先端面における開口部の内周側すなわち軸線O側には、切屑排出溝2のドリル回転方向Tを向く壁面の内周部を軸線O側に切り欠くようにしてシンニング部6が形成されている。このシンニング部6には、ドリル回転方向Tを向くシンニング面6Aと、ドリル回転方向T後方側を向いてドリル回転方向T側に隣接する先端逃げ面3の上記第2逃げ面3Bと交差するシンニング壁面6Bとが形成されており、このシンニング壁面6Bは本実施形態ではドリル本体1先端部の外周にまで達するように延びている。   Further, on the inner peripheral side of the opening in the tip end surface of the drill body 1 of the chip discharge groove 2, that is, on the axis O side, the inner peripheral part of the wall surface facing the drill rotation direction T of the chip discharge groove 2 is notched to the axis O side. Thus, a thinning portion 6 is formed. The thinning portion 6 includes a thinning surface 6A facing the drill rotation direction T and a thinning that faces the rear side of the drill rotation direction T and intersects the second flank 3B of the tip flank 3 adjacent to the drill rotation direction T side. A wall surface 6B is formed, and the thinning wall surface 6B extends to reach the outer periphery of the tip of the drill body 1 in this embodiment.

上記切刃4には、該切刃4の外周端から内周側に延びる主切刃4Aと、この主切刃4Aの内周に連なり、上記シンニング部6のシンニング面6Aと先端逃げ面3(第1逃げ面3A)との交差稜線部に形成されるシンニング刃4Bとが形成されている。切屑排出溝2のドリル回転方向Tを向く上記壁面は主切刃4Aのすくい面とされて、切屑排出溝2が上述のように捩れることにより主切刃4Aには正のすくい角が与えられるとともに、シンニング面6Aがシンニング刃4Bのすくい面とされる。   The cutting edge 4 includes a main cutting edge 4A extending from the outer peripheral end of the cutting edge 4 to the inner peripheral side, and an inner periphery of the main cutting edge 4A. The thinning surface 6A of the thinning portion 6 and the tip flank 3 A thinning blade 4B formed at a crossing ridge line portion with (first flank 3A) is formed. The wall surface of the chip discharge groove 2 facing the drill rotation direction T is a rake face of the main cutting edge 4A, and the main cutting edge 4A is given a positive rake angle by twisting the chip discharge groove 2 as described above. In addition, the thinning surface 6A is a rake face of the thinning blade 4B.

本実施形態では、軸線O方向先端側から見て図2に示すように、主切刃4Aは直線状に延びるように形成されるとともに、シンニング刃4Bは、主切刃4Aに接する凸曲線状をなす接続部4Cを介して該主切刃4Aに接続され、この接続部4Cから主切刃4Aに鈍角に交差する方向に該接続部4Cに接する直線状をなして軸線O側に延びている。接続部4Cは半径Rの円弧とされ、このような接続部4Cは、シンニング面6Aの主切刃4A側を上記半径Rの円筒面状とすることにより形成される。   In the present embodiment, as shown in FIG. 2 when viewed from the front end side in the axis O direction, the main cutting edge 4A is formed so as to extend linearly, and the thinning blade 4B has a convex curve shape in contact with the main cutting edge 4A. Is connected to the main cutting edge 4A through the connecting portion 4C, and extends in the direction intersecting the obtuse angle from the connecting portion 4C to the main cutting edge 4A in a straight line shape and extends toward the axis O. Yes. The connecting portion 4C is an arc having a radius R, and such a connecting portion 4C is formed by making the main cutting edge 4A side of the thinning surface 6A into a cylindrical surface shape having the radius R.

さらに、主切刃4Aの少なくとも接続部4C側にはホーニングが施されてホーニング面7が形成されており、本実施形態では主切刃4Aの全長にホーニング面7が形成されている。このホーニングは、図3に示すように正のすくい角をなす主切刃4Aのすくい面と先端逃げ面3(第1逃げ面3A)との交差稜線部を断面直線状に面取りしたチャンファーホーニングであって、ホーニング面7のホーニング角θは0°または負角とされて、本実施形態では0°とされており、すなわちホーニング面7は軸線Oに平行とされている。   Furthermore, honing is performed on at least the connection portion 4C side of the main cutting edge 4A to form a honing surface 7, and in this embodiment, the honing surface 7 is formed over the entire length of the main cutting edge 4A. As shown in FIG. 3, this honing is performed by chamfer honing in which a cross ridge line portion between the rake face of the main cutting edge 4A having a positive rake angle and the tip flank 3 (first flank 3A) is chamfered in a straight section. The honing angle θ of the honing surface 7 is 0 ° or a negative angle, and is 0 ° in the present embodiment, that is, the honing surface 7 is parallel to the axis O.

なお、ホーニング面7の幅、すなわちホーニング幅は0.005mm〜0.2mmの範囲内とされるのが望ましい。また、このホーニング面7と先端逃げ面3との交差稜線部4Dには、さらに曲率半径が0.01mm〜0.02mm程度の断面凸曲線(凸円弧)をなす微小面取りが形成されていてもよく、こうして微小面取りが形成された場合には、ホーニング面7の幅はこの微小面取りの曲率半径よりも大きくされる。   In addition, it is desirable that the width of the honing surface 7, that is, the honing width is in the range of 0.005 mm to 0.2 mm. Further, even if a minute chamfer forming a convex cross section (convex arc) having a radius of curvature of about 0.01 mm to 0.02 mm is formed on the intersecting ridgeline portion 4D of the honing surface 7 and the tip flank 3. When the minute chamfer is formed in this way, the width of the honing surface 7 is made larger than the curvature radius of the minute chamfer.

そして、シンニング刃4Bのすくい面とされる上記シンニング面6Aのすくい角は、このホーニング面7の上記ホーニング角θと等しくされており、これによってホーニング面7とシンニング面6Aとは滑らかに連続するように形成される。すなわち、本実施形態では、シンニング刃4Bのすくい角は0°とされて、シンニング面6Aも軸線Oと平行に延びることになる。   The rake angle of the thinning surface 6A, which is the rake face of the thinning blade 4B, is made equal to the honing angle θ of the honing surface 7, whereby the honing surface 7 and the thinning surface 6A are smoothly continuous. Formed as follows. That is, in this embodiment, the rake angle of the thinning blade 4B is set to 0 °, and the thinning surface 6A also extends parallel to the axis O.

このような構成のドリルでは、切刃4においてシンニング刃4Bの主切刃4A側に、軸線O方向先端側から見て主切刃4Aに接する凸曲線(本実施形態では半径Rの凸円弧)状をなす接続部4Cが形成されていて、直線状のシンニング刃と主切刃が直接交差するようなことがなく、この接続部4Cを介してシンニング刃4Bが主切刃4Aと接続されているので、主切刃4Aとシンニング刃4Bとが連なる部分における切刃4の強度を確保することができる。なお、接続部4Cは、軸線O方向先端側から見て複数の極短い直線よりなる凸曲した折れ線状であっても同様の効果を得ることができる。   In the drill having such a configuration, a convex curve (a convex arc having a radius R in the present embodiment) in contact with the main cutting edge 4A when viewed from the front end side in the axis O direction on the cutting edge 4 on the main cutting edge 4A side of the thinning blade 4B. 4C is formed so that the straight thinning blade and the main cutting edge do not cross each other directly, and the thinning blade 4B is connected to the main cutting edge 4A via this connection portion 4C. Therefore, the strength of the cutting edge 4 at the portion where the main cutting edge 4A and the thinning edge 4B are continuous can be ensured. Note that the same effect can be obtained even if the connecting portion 4C has a bent polygonal shape consisting of a plurality of extremely short straight lines when viewed from the front end side in the axis O direction.

さらに、主切刃4Aにはホーニングが施されてホーニング面7が形成されているので、主切刃4Aにおける切刃強度も確保することができる。そして、このホーニング面7のホーニング角θと、接続部4Cも含めたシンニング刃4Bのすくい面であるシンニング面6Aのすくい角とが互いに等しくされていて、ホーニング面7とシンニング面6Aとが滑らかに連続しているので、シンニング刃4Bに別途ホーニングを施すことによってシンニング刃4Bの切れ味を損なったりすることなく、シンニング刃4Bの強度も確保することができる。   Furthermore, since the main cutting edge 4A is honed to form the honing surface 7, the cutting edge strength of the main cutting edge 4A can be ensured. The honing angle θ of the honing surface 7 and the rake angle of the thinning surface 6A, which is the rake face of the thinning blade 4B including the connecting portion 4C, are equal to each other, and the honing surface 7 and the thinning surface 6A are smooth. Therefore, the strength of the thinning blade 4B can be secured without impairing the sharpness of the thinning blade 4B by honing the thinning blade 4B separately.

従って、上記構成のドリルによれば、大きなスラスト荷重が作用するドリル本体1先端内周側の主切刃4Aからシンニング刃4Bにかけての部分全体において切刃4の強度を十分に確保することができ、たとえこの切刃4が形成される刃先部が超高硬度である反面、脆くて欠け易い上述のような超高圧焼結体によって形成されていても、切刃4に欠損やチッピングが生じるのを防ぐことができる。さらに、シンニング刃4Bの切れ味は維持することができるので、切削抵抗が増大するのを抑制してスラスト荷重自体の低減を図ることができる。   Therefore, according to the drill having the above-described configuration, the strength of the cutting edge 4 can be sufficiently ensured in the entire portion from the main cutting edge 4A to the thinning edge 4B on the inner peripheral side of the tip of the drill body 1 where a large thrust load acts. Even if the cutting edge 4 on which the cutting edge 4 is formed is ultra-high hardness, the cutting edge 4 is chipped or chipped even if it is formed of the above-described ultra-high pressure sintered body that is brittle and easily chipped. Can be prevented. Furthermore, since the sharpness of the thinning blade 4B can be maintained, the thrust load itself can be reduced by suppressing the cutting resistance from increasing.

ここで、接続部4Cが軸線O方向先端側から見てなす凸曲線の曲率半径(本実施形態では凸円弧の半径R)は、切刃4の外径D、すなわち切刃4の外周端が軸線O回りになす円の直径に対して、0.1×D以上とされるのが望ましく、0.2×D以上とされるのがより望ましい。この曲率半径が0.1×Dよりも小さいと、接続部4Cが尖った角部に近くなって該接続部4Cに欠損等が生じ易くなるおそれがある。   Here, the radius of curvature of the convex curve (in this embodiment, the radius R of the convex arc) formed by the connecting portion 4C when viewed from the front end side in the axis O direction is the outer diameter D of the cutting edge 4, that is, the outer peripheral end of the cutting edge 4. The diameter of the circle formed around the axis O is preferably 0.1 × D or more, and more preferably 0.2 × D or more. If the radius of curvature is smaller than 0.1 × D, the connecting portion 4C may be close to a sharp corner, and the connecting portion 4C may be easily damaged.

また、この凸曲線の曲率半径の上限は0.5×Dとされるのが望ましく、これよりも曲率半径が大きいと、主切刃4Aに接するように接続部4Cを形成するためには接続部4Cが長くなりすぎてしまうおそれがある。なお、上述のように接続部4Cが複数の短い直線によって凸曲する折れ線状に形成されている場合には、これらの直線に内接する円の半径を上記曲率半径とすればよい。   The upper limit of the radius of curvature of the convex curve is desirably 0.5 × D. If the radius of curvature is larger than this, a connection is required to form the connecting portion 4C so as to contact the main cutting edge 4A. The part 4C may become too long. In addition, as above-mentioned, when the connection part 4C is formed in the broken line shape which curves by several short straight lines, what is necessary is just to let the radius of the circle | round | yen inscribed in these straight lines be the said curvature radius.

さらに、主切刃4Aのホーニング面7と先端逃げ面3との交差稜線部4Dに上述のような断面凸曲線をなす微小面取りを形成することにより、一層確実に切刃4の欠損等を防止することができる。このような微小面取りは、接続部4Cも含めたシンニング刃4Bのシンニング面6Aと先端逃げ面3との交差稜線部に延長されていてもよく、この場合には切刃4の全長に亙って欠損を一層確実に防ぐことが可能となる。   Furthermore, by forming the fine chamfering having a convex cross-section as described above at the intersecting ridge line portion 4D between the honing surface 7 and the tip flank 3 of the main cutting edge 4A, it is possible to prevent the cutting edge 4 from being broken more reliably. can do. Such minute chamfering may be extended to the intersection ridge line portion between the thinning surface 6A of the thinning blade 4B including the connecting portion 4C and the tip flank 3, and in this case, it extends over the entire length of the cutting blade 4. This makes it possible to prevent loss more reliably.

次に、上述した接続部4Cが軸線O方向先端側見てなす凸曲線の曲率半径について、実施例を挙げてその効果について説明する。本実施例では、刃先部がダイヤモンド焼結体によって形成された図1ないし図3に示した上記実施形態のドリルにおいて、切刃4の外径Dを10mmとし、接続部4Cがなす凸円弧の半径Rを0.5mm(0.05×D)としたドリルと、半径Rを1.0mm(0.1×D)としたドリルとを製造した。なお、ホーニング面7の幅はいずれも0.005mmであり、交差稜線部4Dに微小面取りは形成されていない。これらを順に実施例1、2とする。   Next, the effect of the curvature radius of the convex curve formed by the connecting portion 4C as seen from the tip side in the axis O direction will be described with reference to examples. In this example, in the drill of the above-described embodiment shown in FIGS. 1 to 3 in which the cutting edge portion is formed of a diamond sintered body, the outer diameter D of the cutting blade 4 is 10 mm, and the convex arc formed by the connecting portion 4C is used. A drill with a radius R of 0.5 mm (0.05 × D) and a drill with a radius R of 1.0 mm (0.1 × D) were manufactured. In addition, the width of the honing surface 7 is 0.005 mm in all, and a minute chamfer is not formed in the intersecting ridge line portion 4D. These are sequentially referred to as Examples 1 and 2.

また、比較例として、シンニング刃の主切刃側に軸線方向先端側から見て主切刃に接する凸曲線状または複数の直線よりなる凸曲した折れ線状をなす接続部を形成せずにシンニング刃と主切刃とを角度をもって直接交差させた(いわゆる、ピンカドとした)以外は実施例1、2と同様のドリルと、さらにこのドリルにおいて主切刃にホーニングを施さなかったドリルも製造した。これらを順に比較例1、2とする。そして、これら実施例1、2と比較例1、2とにより、厚さ5mmのCFRP(炭素繊維強化プラスチック)と厚さ10mmのチタン板とを接合した複合材よりなる被削材に貫通穴をあける穴明け加工を行い、1穴加工ごとに切刃の欠損の有無を確認した。なお、加工条件は、ドリル本体1の回転速度15m/min、送り0.05mm/revで、深さ1mmごとのステップ送りとし、クーラント穴5からは0.5MPaでミスト状クーラントを供給した。   Also, as a comparative example, thinning is not performed on the main cutting edge side of the thinning blade without forming a connecting part that forms a convex curve shape or a curved line shape that is in contact with the main cutting edge when viewed from the axial front end side. A drill similar to Examples 1 and 2 except that the blade and the main cutting edge were directly intersected at an angle (so-called pin caddy) and a drill in which the main cutting blade was not honed in this drill were also manufactured. . These are referred to as Comparative Examples 1 and 2 in this order. Then, according to Examples 1 and 2 and Comparative Examples 1 and 2, a through-hole is formed in a work material made of a composite material in which a CFRP (carbon fiber reinforced plastic) having a thickness of 5 mm and a titanium plate having a thickness of 10 mm are joined. Drilling was performed, and the presence or absence of a cutting edge defect was confirmed for each drilling. The machining conditions were a drill body 1 with a rotational speed of 15 m / min, a feed of 0.05 mm / rev, a step feed for each depth of 1 mm, and mist coolant was supplied from the coolant hole 5 at 0.5 MPa.

その結果、比較例1、2では1穴目を加工する途中で接続部に欠損が発生して寿命となり、1穴も加工することができなかったのに対し、実施例1では1穴は加工を行うことが可能であり、さらに実施例2では5穴加工することが可能であった。ちなみに、実施例2と同じく半径Rが1.0mm(0.1×D)で、ホーニング面7の幅を0.01mmとしたものでは同一の加工条件で10穴加工が可能であり、ホーニング面7の幅を0.2mmとしたものではさらに30穴加工が可能であった。また、ホーニング面7の幅を0.2mmとして半径Rを3.0mm(0.3×D)としたものでは100穴加工した後でも欠損等は認められず、その時点で加工試験を終了した。さらに、同じく半径Rを3.0mm(0.3×D)とし、ただしホーニング面7の幅を0.4mmと大きくしたものでは、同様に100穴加工しても欠損は認められなかったが、加工初期からバリが発生しているのが確認された。   As a result, in Comparative Examples 1 and 2, a defect occurred in the connecting portion during the processing of the first hole, resulting in a life failure. In Example 1, one hole was processed. In Example 2, it was possible to machine 5 holes. Incidentally, 10 holes can be machined under the same machining conditions when the radius R is 1.0 mm (0.1 × D) and the width of the honing surface 7 is 0.01 mm as in the second embodiment. When the width of 7 was 0.2 mm, 30 holes could be further processed. In addition, in the case where the width of the honing surface 7 was 0.2 mm and the radius R was 3.0 mm (0.3 × D), no defects were recognized even after 100 holes were machined, and the machining test was finished at that time. . Further, in the case where the radius R is set to 3.0 mm (0.3 × D), and the width of the honing surface 7 is increased to 0.4 mm, no defects were recognized even when 100 holes were processed, It was confirmed that burrs were generated from the beginning of processing.

1 ドリル本体
2 切屑排出溝
3 先端逃げ面
4 切刃
4A 主切刃
4B シンニング刃
4C 接続部
4D ホーニング面7と先端逃げ面3との交差稜線部
6 シンニング部
6A シンニング面
7 ホーニング面
O ドリル本体1の軸線
T ドリル回転方向
R 軸線O方向先端側から見て接続部4Cがなす凸曲線の曲率半径
θ ホーニング角
DESCRIPTION OF SYMBOLS 1 Drill main body 2 Chip discharge groove 3 Tip flank 4 Cutting blade 4A Main cutting blade 4B Thinning blade 4C Connection part 4D Intersection ridgeline of honing surface 7 and tip flank 3 6 Thinning portion 6A Thinning surface 7 Honing surface O Drill body 1 axis T drill rotation direction R radius of curvature of the convex curve formed by the connecting portion 4C when viewed from the front end side in the axis O direction honing angle

Claims (3)

軸線回りに回転されるドリル本体の先端部外周に切屑排出溝が形成され、この切屑排出溝のドリル回転方向を向く壁面と上記ドリル本体の先端逃げ面との交差稜線部に切刃が形成されたドリルであって、上記切刃は、該切刃の外周端から内周側に延びる主切刃と、上記切屑排出溝のドリル回転方向を向く壁面の内周部を上記軸線側に切り欠くように形成されたシンニング部のドリル回転方向を向くシンニング面と上記先端逃げ面との交差稜線部に形成されて上記主切刃の内周に連なるシンニング刃とを備え、このシンニング刃は、上記軸線方向先端側から見て上記主切刃に接する凸曲線状または複数の直線よりなる凸曲した折れ線状をなす接続部を介して該主切刃に接続されるとともに、上記主切刃の少なくとも上記接続部側にはホーニングが施されてホーニング面が形成されており、このホーニング面のホーニング角は上記シンニング面による上記シンニング刃のすくい角と等しくされていて、上記ホーニング面とシンニング面とが滑らかに連続していることを特徴とするドリル。   A chip discharge groove is formed on the outer periphery of the tip end of the drill body rotated about the axis, and a cutting edge is formed at a crossed ridge line portion between the wall surface of the chip discharge groove facing the drill rotation direction and the tip flank of the drill body. The cutting blade has a main cutting edge extending from the outer peripheral end of the cutting blade to the inner peripheral side, and an inner peripheral portion of the wall surface facing the drill rotation direction of the chip discharge groove cut out to the axial line side. A thinning blade formed on the intersecting ridge line portion of the thinning portion facing the drill rotation direction of the thinning portion and the tip flank and connected to the inner periphery of the main cutting blade. The main cutting edge is connected to the main cutting edge via a connecting portion having a convex curve shape or a curved line consisting of a plurality of straight lines in contact with the main cutting edge when viewed from the front end side in the axial direction. Honing on the connection side The honing surface is formed, the honing angle of the honing surface is equal to the rake angle of the thinning blade by the thinning surface, and the honing surface and the thinning surface are smoothly continuous. Features a drill. 上記軸線方向先端側から見て上記接続部がなす凸曲線の曲率半径または凸曲した折れ線に内接する円の半径が、上記切刃の外径Dに対して0.1×D以上とされていることを特徴とする請求項1に記載のドリル。   The radius of curvature of the convex curve formed by the connecting portion or the circle inscribed in the convex bent line when viewed from the front end side in the axial direction is 0.1 × D or more with respect to the outer diameter D of the cutting edge. The drill according to claim 1, wherein: 上記ホーニング面と上記先端逃げ面との交差稜線部には、断面凸曲線状の面取りが施されていることを特徴とする請求項1または請求項2に記載のドリル。   3. The drill according to claim 1, wherein a chamfer having a convex cross-sectional shape is applied to an intersecting ridge line portion between the honing surface and the tip flank. 4.
JP2013071102A 2013-03-29 2013-03-29 Drill Pending JP2014193513A (en)

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2018079489A1 (en) * 2016-10-26 2018-05-03 京セラ株式会社 Cutting tool and method for producing cutting workpiece
WO2019224862A1 (en) * 2018-05-21 2019-11-28 オーエスジー株式会社 Drill
US10646934B2 (en) * 2017-07-27 2020-05-12 Sumitomo Electric Hardmetal Corp. Drill
EP3639956A4 (en) * 2017-06-13 2021-03-17 Sumitomo Electric Hardmetal Corp. Drill

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Publication number Priority date Publication date Assignee Title
WO2018079489A1 (en) * 2016-10-26 2018-05-03 京セラ株式会社 Cutting tool and method for producing cutting workpiece
JP7216698B2 (en) 2016-10-26 2023-02-01 京セラ株式会社 Manufacturing method for cutting tools and cut products
EP3639956A4 (en) * 2017-06-13 2021-03-17 Sumitomo Electric Hardmetal Corp. Drill
US11141799B2 (en) 2017-06-13 2021-10-12 Sumitomo Electric Hardmetal Corp. Drill
US10646934B2 (en) * 2017-07-27 2020-05-12 Sumitomo Electric Hardmetal Corp. Drill
WO2019224862A1 (en) * 2018-05-21 2019-11-28 オーエスジー株式会社 Drill
JPWO2019224862A1 (en) * 2018-05-21 2020-05-28 オーエスジー株式会社 Drill
KR20200090257A (en) * 2018-05-21 2020-07-28 오에스지 가부시키가이샤 drill
EP3797910A4 (en) * 2018-05-21 2022-02-09 OSG Corporation Drill
KR102381868B1 (en) * 2018-05-21 2022-04-04 오에스지 가부시키가이샤 drill
US11407040B2 (en) 2018-05-21 2022-08-09 Osg Corporation Drill

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