JPS6222725B2 - - Google Patents
Info
- Publication number
- JPS6222725B2 JPS6222725B2 JP1108779A JP1108779A JPS6222725B2 JP S6222725 B2 JPS6222725 B2 JP S6222725B2 JP 1108779 A JP1108779 A JP 1108779A JP 1108779 A JP1108779 A JP 1108779A JP S6222725 B2 JPS6222725 B2 JP S6222725B2
- Authority
- JP
- Japan
- Prior art keywords
- chips
- cutting edge
- cutting
- drill
- blade
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 230000002093 peripheral effect Effects 0.000 claims description 4
- 238000013459 approach Methods 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
Landscapes
- Drilling Tools (AREA)
Description
【発明の詳細な説明】
本発明は、切削性能がすぐれ、かつねじれ溝の
摩耗の少ないドリルに関するものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a drill that has excellent cutting performance and reduces wear on the helical groove.
従来のドリルは、チゼル部の矛盾を未解決のま
まにしているために、切味と切屑の排出に重点を
おいたドリルでは剛性が不足し、剛性の高いドリ
ルは切味が悪く重切屑に不向きであつた。また、
近年被削材中には難削材、高硬度材も多く含まれ
るようになつてきており、ドリルにも超硬合金の
採用が必要となつてきたが、中心部では切削速度
が零に近いうえにチゼル部分のすくい角は極端な
負角となるために刃物としての効果が期待でき
ず、送り量に相当する圧縮荷重をうけることにな
る。このような欠点を解消するものとしていわゆ
るうず巻刃ドリルが提案されているが、このドリ
ルでは切刃によつて生成された切屑はねじれ溝中
の対向する壁、即ち回転方向前方の壁に押しつけ
られることによつて塑性変形して丸められること
になる。この際の切屑による摩擦によつてねじれ
溝の壁が摩耗し、この現象がドリルの寿命を著し
く短かくする。 Conventional drills leave the contradiction in the chisel part unresolved, so drills that focus on sharpness and evacuation of chips lack rigidity, and drills with high rigidity have poor cutting performance and produce heavy chips. It was not suitable for me. Also,
In recent years, work materials have come to include many difficult-to-cut materials and high-hardness materials, and it has become necessary to use cemented carbide for drills, but the cutting speed in the center is close to zero. Moreover, the rake angle of the chisel part is extremely negative, so it cannot be expected to be effective as a cutting tool, and is subject to a compressive load corresponding to the feed amount. A so-called spiral-blade drill has been proposed to overcome these drawbacks, but in this drill, the chips generated by the cutting blade are pressed against the opposing wall in the helical groove, that is, the wall in front of the rotation direction. This results in plastic deformation and rounding. The friction caused by the chips at this time causes the walls of the helical groove to wear out, and this phenomenon significantly shortens the life of the drill.
本発明はこのような問題の解決のためになされ
たものであり、渦巻き刃ドリルにおいて切刃形状
を改良することにより、切屑が一定の位置に押し
つけられないようにし、これによつてドリルの寿
命の増大を図つたものである。 The present invention was made to solve these problems, and by improving the shape of the cutting edge of a spiral-blade drill, chips are not forced into a fixed position, thereby extending the life of the drill. The aim is to increase the number of people.
以下、本発明を実施例の図面によつて説明す
る。１はシヤンク、２，２は一対のチツプ、３，
３はシヤンク１に形成されたねじれ溝である。シ
ヤンク１の頭部は円錐状で、その頂点となる中心
点１０を始端として互いに点対称の切刃４，４が
チツプ２，２に形成されている。この切刃４，４
は、軸線方向先端視において回転方向に凸なる曲
線をなし、かつ外周部から中心部に近づくほど曲
率が大きくなるような渦巻き状の曲線となつてい
る。このような切刃形状を採用すると、切屑の厚
さは切刃のＲに比例するから切屑は外周部に比べ
て中心部が薄くなり、切削抵抗も小さく、また切
屑も切刃に圧着されることがないためにスムース
に排出される。しかしながら、切刃によつて生成
された切屑は第１図および第２図の矢印Ａで示す
ように、ねじれ溝中の対向する壁に押しつけられ
て丸められ、第４図に示すような切屑４０が生
じ、この切屑４０による摩擦によつて壁が局部的
に摩耗し、ねじれ溝の稜線３１の部分に凹部５が
形成される。この凹部５が形成されるとねじれ溝
の曲率が小さくなるために後続する切屑の巻き半
径は大きくなる。そしてこの切屑がねじれ溝中を
上昇すると、ねじれ溝は凹部の形成されていない
部分では曲率が大きいために切屑をより大きな曲
率に再変形させることになり、またこの際切屑は
加工孔の内面にも押しつけられることになつてド
リルの主軸に大きな負担をかけ、かつ切屑の排出
にも支障をきたすようになる。 Hereinafter, the present invention will be explained with reference to drawings of embodiments. 1 is a shank, 2, 2 is a pair of chips, 3,
3 is a twisted groove formed in the shank 1. The head of the shank 1 is conical, and cutting edges 4, 4 are formed on the tips 2, 2, which are symmetrical with respect to each other, with the starting end being a center point 10, which is the apex of the head. This cutting blade 4,4
is a spiral curve that is convex in the rotational direction when viewed from the axial tip, and has a larger curvature as it approaches the center from the outer periphery. When such a cutting edge shape is adopted, the thickness of the chips is proportional to the radius of the cutting edge, so the chips are thinner at the center compared to the outer periphery, the cutting resistance is small, and the chips are also crimped onto the cutting edge. It is discharged smoothly because there is no problem. However, the chips generated by the cutting blade are pressed against the opposing walls of the helical groove as shown by arrow A in FIGS. 1 and 2 and are rounded, resulting in chips 40 as shown in FIG. The friction caused by the chips 40 causes local wear of the wall, and a recess 5 is formed at the ridge line 31 of the helical groove. When the recess 5 is formed, the curvature of the helical groove becomes smaller, so that the winding radius of the subsequent chips becomes larger. When the chips rise in the helical groove, the helical groove has a large curvature in the part where the recess is not formed, so the chips are re-deformed to a larger curvature, and at this time, the chips are forced into the inner surface of the machined hole. This puts a heavy burden on the main shaft of the drill, and also impedes the evacuation of chips.
しかるに本発明においては、切刃４，４の端部
にはその部分を斜めにカツトして端部切刃６を形
成している。この端部切刃６は、外周附近でほぼ
直線の切刃４に対し急激に方向を変えて形成され
ているために、これによつて生成される切屑４１
は第６図に示すように一定量だけ丸められた後に
直線的に延びた部分が形成される。このような形
状になるのは、従来の切屑４０はその横断面が第
５図に示すように直線的であるため曲げられやす
いのに対し、本発明によつて生成される切屑４１
の横断面は第７図に示すように端部切刃６に対応
する部分で屈曲し、このため切屑４１の曲げ剛性
が大きくなつて切屑が曲げられにくくなり、中心
部分刃先で切削された薄い部分の切屑を引きさ
き、生成途中で上向きに押し出されるようになる
ためである。即ち、切屑の生成当初は切屑は矢印
Ａで示す経路で進んで丸められるが、途中から端
部切刃６によつて生成した第７図に示すような曲
げ剛性の大きな部分のために矢印Ｂに示す方向に
切屑の移動経路が変化する。このように、生成す
る切屑の移動経路が変化すると、切屑が押しつけ
られる部分は広範囲にわたるために局部的な摩耗
は防止される。なお、端部切刃６はこのような作
用を果すものであればとくにその形状には限定が
なく、図示のような直線的にカツトしたものに限
らず、曲線によるカツトであつてもよい。 However, in the present invention, end cutting edges 6 are formed at the ends of the cutting edges 4 by cutting the portions diagonally. Since this end cutting edge 6 is formed by abruptly changing direction with respect to the substantially straight cutting edge 4 near the outer periphery, chips 41 generated thereby
As shown in FIG. 6, after being rounded by a certain amount, a linearly extending portion is formed. The reason for this shape is that the conventional chips 40 have a straight cross section as shown in FIG. 5 and are easily bent, whereas the chips 41 produced by the present invention
As shown in FIG. 7, the cross-section of This is because the chips in the part are pulled out and are pushed upward during the production process. That is, at the beginning of the generation of chips, the chips proceed along the path shown by arrow A and are rounded, but from the middle of the formation, the chips travel along the path shown by arrow B due to the portion with high bending rigidity as shown in FIG. 7, which is generated by the end cutting edge 6. The movement path of the chips changes in the direction shown in . In this way, when the movement path of the generated chips changes, the area against which the chips are pressed is spread over a wide range, thereby preventing local wear. The shape of the end cutting edge 6 is not particularly limited as long as it can perform such an action, and it is not limited to a straight cut as shown in the figure, but may be a curved cut.
すなわち、図示の例では軸線方向先端視におけ
る切刃の形状は外周端部より内側はほぼ直線に形
成され、外周端部ではドリルの回転方向後方に折
曲げられた形状の端部切刃６が形成され、この端
部切刃６は第３図に示すように直線的になつてい
るが、この第３図における端部切刃６の形状が曲
線であつてもよい。 That is, in the illustrated example, the shape of the cutting edge when viewed from the tip in the axial direction is formed into a substantially straight line on the inside from the outer peripheral end, and at the outer peripheral end, the end cutting blade 6 is bent rearward in the rotational direction of the drill. Although the end cutting edge 6 is straight as shown in FIG. 3, the end cutting edge 6 in FIG. 3 may have a curved shape.
以上説明したように、本発明は切刃の形状を改
良することによつて切屑の生成経路が変化するよ
うにし、これによつて切削性能のすぐれた渦巻き
刃ドリルにおいてねじれ溝の局部的な摩耗が生じ
るのを防止するようにしたものである。 As explained above, the present invention improves the shape of the cutting edge to change the path of chip generation, thereby reducing the local wear of the helical groove in a spiral blade drill with excellent cutting performance. This is designed to prevent this from occurring.
第１図は本発明のドリルの側面図、第２図は第
１図の右側面図、第３図はその底面図、第４図は
従来品の切屑の斜視図、第５図はその―線断
面図、第６図は本発明品の切屑の斜視図、第７図
はその―線断面図である。
１……シヤンク、２……切刃、３……ねじれ
溝、４……切刃、５……凹部、４０……従来の切
屑、４１……本発明の切屑。
Fig. 1 is a side view of the drill of the present invention, Fig. 2 is a right side view of Fig. 1, Fig. 3 is a bottom view thereof, Fig. 4 is a perspective view of chips of the conventional product, and Fig. 5 is its - 6 is a perspective view of the chips of the product of the present invention, and FIG. 7 is a sectional view taken along the line -. DESCRIPTION OF SYMBOLS 1... Shank, 2... Cutting edge, 3... Twisted groove, 4... Cutting edge, 5... Recessed part, 40... Conventional chips, 41... Chips of the present invention.
Claims (1)
刃はその始端部が回転中心にあつて互いに点対称
に配置され、各切刃は回転方向に対して凸なる曲
線をなし、かつ外周部の切刃曲線より中心部の切
刃の曲線の方が大きな曲率をなすように構成し、
各切刃の外周端部より内側はほぼ直線に形成さ
れ、外周端部ではドリルの回転方向後方に折曲げ
られた形状の端部切刃を形成したことを特徴とす
るドリル。1 When viewed from the tip in the axial direction of the drill, the pair of cutting edges are arranged point-symmetrically with the starting end at the center of rotation, each cutting edge forms a convex curve with respect to the rotation direction, and the cutting edge on the outer periphery The cutting edge curve in the center has a larger curvature than the blade curve.
A drill characterized in that the inner side of the outer peripheral end of each cutting blade is formed into a substantially straight line, and the outer peripheral end has an end cutting blade bent rearward in the rotational direction of the drill.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1108779A JPS55106709A (en) | 1979-02-01 | 1979-02-01 | Drill |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1108779A JPS55106709A (en) | 1979-02-01 | 1979-02-01 | Drill |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS55106709A JPS55106709A (en) | 1980-08-15 |
| JPS6222725B2 true JPS6222725B2 (en) | 1987-05-19 |
Family
ID=11768192
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1108779A Granted JPS55106709A (en) | 1979-02-01 | 1979-02-01 | Drill |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS55106709A (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4984944A (en) * | 1987-02-09 | 1991-01-15 | Vermont American Corporation | Drill bit blade for masonry and rock drill |
| US5230593A (en) * | 1987-12-14 | 1993-07-27 | Mitsubishi Kinzoku Kabushiki Kaisha | Twist drill |
| EP0320881B2 (en) * | 1987-12-14 | 2003-10-22 | Mitsubishi Materials Corporation | Twist drill |
| US8061938B2 (en) * | 2008-03-10 | 2011-11-22 | Kennametal Inc. | Cutting tool with chisel edge |
-
1979
- 1979-02-01 JP JP1108779A patent/JPS55106709A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS55106709A (en) | 1980-08-15 |
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