JP2001121307A - Cutting tool - Google Patents
Cutting toolInfo
- Publication number
- JP2001121307A JP2001121307A JP30776299A JP30776299A JP2001121307A JP 2001121307 A JP2001121307 A JP 2001121307A JP 30776299 A JP30776299 A JP 30776299A JP 30776299 A JP30776299 A JP 30776299A JP 2001121307 A JP2001121307 A JP 2001121307A
- Authority
- JP
- Japan
- Prior art keywords
- cutting
- tool
- shank portion
- blind hole
- shank
- 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.)
- Withdrawn
Links
Landscapes
- Cutting Tools, Boring Holders, And Turrets (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、各種ワークを切削
加工する切削工具に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cutting tool for cutting various works.
【０００２】[0002]
【従来の技術】例えば、下穴が形成されたワークに内周
加工を施すための中ぐり用の工具として中ぐりバイトが
知られており、この中ぐりバイトは略円柱状をなす中実
の工具本体のヘッド部先端に例えば超硬合金製のチップ
を着脱可能に装着している。この中ぐりバイトは、シャ
ンク部を工作機械の主軸に支持されて高速で回転するワ
ークの下穴に挿入され、チップに形成された切刃によっ
て下穴の内周面を切削加工していくものである。中ぐり
バイトは、工具本体のシャンク部を工作機械に把持され
て軸状の工具本体を長く突き出した状態で切削を行うも
のであるため、切削加工時にビビリ振動が発生し易い。
このため、従来は工具本体の剛性を高めてたわみによる
振動を抑制すべく、切屑排出の邪魔にならない範囲でヘ
ッド部を大径化したり、工具本体を総ハイス製にして剛
性を高めること等によってビビリ振動の発生を抑制しよ
うとしていた。2. Description of the Related Art For example, a boring tool is known as a boring tool for performing inner peripheral processing on a workpiece having a prepared hole, and the boring tool is a substantially cylindrical solid boring tool. A tip made of, for example, a cemented carbide is detachably attached to the tip of the head portion of the tool body. This boring tool inserts the shank part into the pilot hole of a workpiece that rotates at high speed while being supported by the main shaft of the machine tool, and cuts the inner peripheral surface of the pilot hole with the cutting blade formed on the tip It is. Since the boring tool performs cutting while the shank portion of the tool body is gripped by the machine tool and the axial tool body is protruded long, chatter vibration is easily generated during the cutting process.
For this reason, conventionally, in order to increase the rigidity of the tool body and suppress vibration due to deflection, by increasing the diameter of the head part as long as it does not hinder chip discharge, or by increasing the rigidity by making the tool body all made of high speed I was trying to suppress the occurrence of chatter vibration.
【０００３】例えば、中実の工具本体に関してヘッド部
をシャンク部に対して大径化することでビビリ振動の発
生を抑制するように構成した中ぐりバイトがある。この
中ぐりバイトで、切屑排出性の向上を図るため、第一の
チップポケットに隣接してヘッド部の外周面に第２のチ
ップポケットを形成し、これを第一のチップポケットに
連通させて切屑を誘導しようとしたものも知られてい
る。しかしながら、これらの場合であっても、バイトが
ワークから受ける外力（切削抵抗）の振動数と、バイト
を含む機械系の固有振動数とが一致した際に起きる共振
によってビビリ振動振幅が増大することは防止できず、
深い下穴の内周面を精度良く仕上げる場合や寸法精度が
厳しく要求されている場合等には十分な加工精度に仕上
げることが困難であった。このような欠点を改善しよう
とした技術として例えば特公昭６３−４８６４１号公報
では、シャンク部の内部に盲状空洞を穿孔することで、
ホルダの太さを落とすことなくその質量を小さく軽量化
して固有振動数を増大させて振動に対してダンパーとし
て機能するようにしたものもある。For example, there is a boring tool configured to suppress the occurrence of chatter vibration by increasing the diameter of a head portion with respect to a shank portion of a solid tool body. With this boring tool, a second chip pocket is formed on the outer peripheral surface of the head portion adjacent to the first chip pocket in order to improve chip dischargeability, and this is communicated with the first chip pocket. It is also known to try to induce chips. However, even in these cases, the chatter vibration amplitude increases due to the resonance that occurs when the frequency of the external force (cutting force) received by the tool from the workpiece matches the natural frequency of the mechanical system including the tool. Cannot be prevented,
In the case where the inner peripheral surface of a deep prepared hole is to be finished with high accuracy, or where dimensional accuracy is strictly required, it has been difficult to finish with sufficient processing accuracy. For example, Japanese Patent Publication No. Sho 63-48641 discloses a technique for remedying such a disadvantage by forming a blind cavity inside a shank portion.
In some cases, the holder is reduced in weight and weight without reducing the thickness of the holder, and the natural frequency is increased to function as a damper against vibration.
【０００４】[0004]
【発明が解決しようとする課題】ところが切削抵抗によ
る振動と固有振動との共振によるビビリ振動を抑制する
ために固有振動数を増大させるべく盲状空洞を大きく設
定すると工具本体の剛性が低下してたわみが増大するた
めにたわみ剛性を損なったりビビリ振動がかえって増大
したりしてワークの加工精度が低下したり工具本体を折
損しやすくなるという欠点が生じていた。本発明は、上
記事情に鑑みてなされたもので、たわみ剛性を確保しつ
つビビリ振動の発生等を防止するようにした切削工具を
提供することを目的とする。However, if the blind cavity is set large so as to increase the natural frequency in order to suppress the chatter vibration caused by the resonance between the vibration caused by the cutting resistance and the natural vibration, the rigidity of the tool body decreases. Due to the increase in the bending, the bending rigidity is impaired, and the chatter vibration is rather increased, so that the machining accuracy of the work is reduced and the tool body is easily broken. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a cutting tool capable of preventing chatter vibration and the like while securing flexural rigidity.
【０００５】[0005]
【課題を解決するための手段】本発明は、従来技術では
想定されていなかった固有振動数とたわみ剛性とをバラ
ンスさせることによってビビリ振動の抑制と加工精度の
向上を図ることに着目したものであって、本発明に係る
切削工具は、工具本体のシャンク部の内部に該シャンク
部の中心軸に沿って延びる中空のめくら穴を形成してな
る切削工具において、シャンク部の中心軸に直交する断
面におけるめくら穴の断面積（Ｓａ）と前記シャンク部
の肉厚部の断面積（Ｓｂ）との比（Ｓａ／Ｓｂ）が０．
２〜１．３の範囲に設定されていることを特徴とする。
シャンク部の軸直交断面において、めくら穴とシャンク
部肉厚部の断面積比を０．２〜１．３の範囲に設定する
ことで、シャンク部の質量を軽量化できると共にたわみ
剛性を十分確保することができ、切削時のビビリ振動と
工具本体のたわみを抑えて加工精度を向上できる。The present invention focuses on suppressing chatter vibration and improving machining accuracy by balancing the natural frequency and flexural rigidity, which were not assumed in the prior art. The cutting tool according to the present invention is a cutting tool having a hollow blind hole extending along the center axis of the shank portion inside the shank portion of the tool body, wherein the cutting tool is orthogonal to the center axis of the shank portion. The ratio (Sa / Sb) of the cross-sectional area (Sa) of the blind hole in the cross-section to the cross-sectional area (Sb) of the thick portion of the shank portion is 0.
It is characterized in that it is set in the range of 2 to 1.3.
By setting the cross-sectional area ratio between the blind hole and the thick part of the shank part in the cross section perpendicular to the axis of the shank part in the range of 0.2 to 1.3, the weight of the shank part can be reduced and the deflection rigidity is sufficiently secured. It is possible to suppress chatter vibration during cutting and deflection of the tool body, thereby improving machining accuracy.
【０００６】また工具本体のヘッド部に切刃を備え、ヘ
ッド部には切刃のすくい面につながるチップポケットと
切刃の逃げ面につながる背部との間の外周面に凹溝が形
成されていてもよい。凹溝によってヘッド部を軽量化す
ればシャンク部を含めて工具本体全体を軽量化できて固
有振動数を著しく増大できて外力即ち切削抵抗による振
動数との乖離を大きくして共振によるビビリ振動を効果
的に抑制できる。しかも凹溝の位置は切刃に対して周方
向反対側の対向する外周面であるから、切屑を走行させ
る切刃のすくい面の領域や切刃の逃げ面を含む領域であ
って切削力の主分力を受ける背部から外れているために
切屑排出性を妨げたりヘッド部及びシャンク部の剛性低
下を来すことがない。Further, a cutting portion is provided in a head portion of the tool body, and a concave portion is formed in an outer peripheral surface of the head portion between a tip pocket connected to a rake face of the cutting edge and a back portion connected to a flank of the cutting edge. You may. If the head part is reduced in weight by the concave groove, the entire tool body including the shank part can be reduced in weight, the natural frequency can be significantly increased, and the divergence from the external force, that is, the frequency due to cutting resistance, is increased, and chatter vibration due to resonance is increased It can be suppressed effectively. Moreover, since the position of the concave groove is the outer peripheral surface opposite to the cutting edge in the circumferential direction, it is the area of the rake face of the cutting blade for running the chips and the area including the flank of the cutting blade and the cutting force Since it is separated from the back receiving the main component force, there is no hindrance to chip discharge and no reduction in rigidity of the head and the shank.
【０００７】また凹溝は、工具本体の先端面と仕切られ
ていてもよい。ヘッド部の先端に凹溝が開口しないこと
で、先端の剛性低下を抑制できる。尚、ヘッド部の凹溝
は１または複数形成されていてもよく、複数の凹溝は工
具本体の長手方向に沿って形成されていてもよい。この
場合、ヘッド部のうち切刃近傍は切削力による主分力と
背分力を受けるために剛性を確保する必要があり、凹溝
を複数で構成すればその位置に応じて受けるべき主分力
と背分力の有無や大小によって凹溝の中心軸線に直交す
る断面積を増減して適宜設定できるから、剛性を低下さ
せない複数の凹溝の設計が容易である。例えば、複数の
凹溝は工具本体の基端側から先端側に向けて、容積が比
較的大きい第一凹溝と比較的小さい第二凹溝が順次形成
されていてもよい。切刃近傍のヘッド部外周面に位置す
る第二凹溝では剛性確保のためにその凹陥部の容積を小
さく設定し、切刃から離れる基端側領域では第一凹溝の
容積を大きく設計することで剛性低下を来すことなく軽
量化を効果的に達成できる例えば第一凹溝の深さを深く
したり幅を広くしたり、第二凹溝の中心軸線Ｏに向かう
深さを浅くしたり、溝の幅を狭くしたりしてもよい。[0007] The concave groove may be partitioned from the tip end surface of the tool body. Since the concave groove does not open at the tip of the head portion, the decrease in rigidity at the tip can be suppressed. One or more grooves may be formed in the head portion, and the plurality of grooves may be formed along the longitudinal direction of the tool body. In this case, it is necessary to secure rigidity in the vicinity of the cutting edge of the head portion in order to receive the main component force and the back component force due to the cutting force. If a plurality of concave grooves are formed, the main component to be received according to the position is required. Since the cross-sectional area perpendicular to the central axis of the groove can be increased or decreased as appropriate according to the presence or absence and magnitude of the force and the back force, the design of a plurality of grooves that does not reduce the rigidity is easy. For example, in the plurality of grooves, a first groove having a relatively large volume and a second groove having a relatively small volume may be sequentially formed from the base end side to the distal end side of the tool body. In the second groove located on the outer peripheral surface of the head portion near the cutting blade, the volume of the concave portion is set small to secure rigidity, and the volume of the first groove is designed large in the base end region away from the cutting blade. For example, it is possible to effectively reduce the weight without lowering the rigidity. For example, the depth of the first groove is increased or the width is increased, and the depth of the second groove toward the central axis O is reduced. Alternatively, the width of the groove may be reduced.
【０００８】[0008]
【発明の実施の形態】以下、本発明の実施の形態につい
て、図１乃至図７により説明する。図１は実施の形態に
よる中ぐりバイトの平面図、図２は図１に示す中ぐりバ
イトのヘッド部を外周刃方向から見た拡大側面図、図３
は同じくヘッド部の拡大先端面図、図４はヘッド部を凹
溝方向から見た拡大側面図、図５は図１に示すシャンク
部のＡ−Ａ線断面図、図６は図４に示すヘッド部の断面
図であって（ａ）はＢ−Ｂ線断面図、（ｂ）はＣ−Ｃ線
断面図、（ｃ）はＤ−Ｄ線断面図、（ｄ）はＥ−Ｅ線断
面図、図７は図６に示すシャンク部の中空部と肉厚部の
断面積比に対するたわみ比及び固有振動数比を示すグラ
フである。図１乃至図４において、中ぐりバイト１の略
棒状をなす工具本体２はヘッド部３とシャンク部４とか
らなり、例えばシャンク部４は略円柱状とされ、ヘッド
部３は例えばシャンク部４との連結部から先端面３ａに
向かって漸次工具本体２の中心軸Ｏに直交する断面積が
小さくなるように形成されている。DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS. FIG. 1 is a plan view of a boring tool according to the embodiment, FIG. 2 is an enlarged side view of a head portion of the boring tool shown in FIG.
4 is an enlarged front view of the head portion, FIG. 4 is an enlarged side view of the head portion viewed from the groove direction, FIG. 5 is a cross-sectional view of the shank portion taken along line AA of FIG. 1, and FIG. 6 is FIG. It is sectional drawing of a head part, (a) is BB sectional drawing, (b) is CC sectional drawing, (c) is DD sectional drawing, (d) is EE sectional drawing. FIG. 7 is a graph showing a deflection ratio and a natural frequency ratio with respect to a sectional area ratio of a hollow portion and a thick portion of the shank portion shown in FIG. 1 to 4, a substantially bar-shaped tool body 2 of a boring tool 1 includes a head portion 3 and a shank portion 4. For example, the shank portion 4 has a substantially columnar shape, and the head portion 3 has, for example, a shank portion 4. Is formed so that the cross-sectional area orthogonal to the central axis O of the tool main body 2 gradually decreases from the connecting portion toward the distal end surface 3a.
【０００９】工具本体２の先端側に位置するヘッド部３
において、その基端側から先端面３ａにかけて外周面３
ｂを切り欠いて凹曲面状の第一凹部６が形成されてい
る。更に工具本体２の第一凹部６の途中部分から先端面
３ａまで外周面３ｂの一部と第一凹部６の一部を切り欠
いてチップポケット７が形成され、このチップポケット
７は中心軸Ｏの方向に例えば第一凹部６の１／２〜２／
３程度の長さとされている。そしてチップポケット７の
一部と外周面３ｂの一部とを切り欠いて第二凹部８が形
成されている。チップポケット７において図１に示すヘ
ッド部３の平面図でヘッド部３の先端角部を切り欠いて
チップ取付座９が形成され、このチップ取付座９にスロ
ーアウェイチップ１０がネジ１１等で固着されている。
固着状態のスローアウェイチップ１０において、チップ
取付座９の底面に着座する着座面１０ａに対向する上面
１０ｂがすくい面とされ、この上面１０ｂの先端側稜辺
をなす前切刃１０ｃがヘッド部３の先端側に突出し、上
面１０ｂの外周側稜辺をなす外周刃１０ｄがヘッド部３
の外周面３ｂから径方向外側に突出している。[0009] A head portion 3 located on the tip side of the tool body 2
, The outer peripheral surface 3 extends from the proximal end side to the distal end surface 3a.
The first concave portion 6 having a concave curved surface shape is formed by cutting out b. Further, a part of the outer peripheral surface 3b and a part of the first concave part 6 are cut out from the middle part of the first concave part 6 of the tool main body 2 to the tip end surface 3a to form a chip pocket 7, and the chip pocket 7 has a central axis O. In the direction of, for example, 1/2 to 2 /
The length is about three. A second recess 8 is formed by cutting out a part of the chip pocket 7 and a part of the outer peripheral surface 3b. In the chip pocket 7, a chip mounting seat 9 is formed by cutting out a corner of the head 3 in the plan view of the head 3 shown in FIG. 1, and a throw-away chip 10 is fixed to the chip mounting seat 9 with a screw 11 or the like. Have been.
In the fixed away insert 10, the upper surface 10b facing the seating surface 10a seated on the bottom surface of the chip mounting seat 9 is a rake face, and the front cutting edge 10c which forms the tip side edge of the upper surface 10b is the head part 3. The outer peripheral blade 10d protruding toward the distal end of the head portion 3 and forming the outer peripheral edge of the upper surface 10b
Protrudes radially outward from the outer peripheral surface 3b.
【００１０】前切刃１０ｃとこれに隣接する稜辺を成す
外周刃１０ｄとが交差する例えば鋭角の角部がノーズ部
１０ｅとされ、外周刃１０ｄは中心軸Ｏと略平行に配置
され前切刃１０ｃは他の角部の一端から他端であるノー
ズ部１０ｅに向けて漸次先端側に突出するように平面視
で傾斜配置されている。またチップポケット７に周方向
に隣接して、第二凹部８から先端面３ａにかけて漸次チ
ップ取付座９側に近づくように略凹曲面状に傾斜する傾
斜面１２が形成されている。この傾斜面１２は図２及び
４において、チップ１０よりも高い位置にある。更に中
心軸Ｏに対して外周刃１０ｄと周方向に約１８０°前後
離れた反対側のヘッド部３の外周面３ｂでは、この外周
面３ｂを基端側から先端面３ａにかけて切除して略凹曲
面状に中心軸Ｏ側に落ち込む凹溝１４が形成されてい
る。この凹溝１４は例えば平面視略楕円状をなす凹曲面
とされて単一の凹部を構成しており、その最も中心軸Ｏ
に近づく底部１４ａはチップ取付座９よりも基端側にズ
レて位置することで、切削力による主分力と背分力を受
ける切刃近傍を避けて配置されているためにヘッド部３
の剛性低下を抑制している。また凹溝１４はヘッド部３
の先端面３ａに開口することなく仕切部２１によって先
端面３ａと仕切られている。尚、チップ１０の側面１０
ｆはノーズ部１０ｅ及び前切刃１０ｃ及び外周刃１０ｄ
の逃げ面をなし、ヘッド部３の先端面３ａを含む背部２
２に続いている。For example, a nose portion 10e is formed at an acute angle where the front cutting edge 10c intersects with an outer peripheral edge 10d forming a ridge adjacent thereto, and the outer peripheral edge 10d is arranged substantially parallel to the central axis O and is formed with a front cutting edge. The blade 10c is inclined in plan view so as to gradually protrude toward the distal end from one end of the other corner toward the nose 10e, which is the other end. An inclined surface 12 is formed adjacent to the chip pocket 7 in the circumferential direction, and is inclined substantially concavely from the second concave portion 8 to the tip end surface 3a so as to gradually approach the chip mounting seat 9 side. This inclined surface 12 is located higher than the chip 10 in FIGS. Further, on the outer peripheral surface 3b of the head portion 3 opposite to the central axis O by about 180 ° in the circumferential direction with respect to the outer peripheral blade 10d, the outer peripheral surface 3b is cut from the base end side to the distal end surface 3a to be substantially concave. A concave groove 14 is formed on the central axis O side in a curved shape. The concave groove 14 is, for example, a concave curved surface having a substantially elliptical shape in a plan view, and forms a single concave portion.
The bottom portion 14a approaching the tip portion 3a is located closer to the base end side than the tip mounting seat 9, and is disposed so as to avoid the vicinity of the cutting blade receiving the main component force and the back component force due to the cutting force.
Of rigidity is suppressed. In addition, the concave groove 14 is formed in the head 3
Is separated from the distal end face 3a by the partition 21 without opening to the distal end face 3a. The side surface 10 of the chip 10
f is a nose portion 10e, a front cutting edge 10c, and an outer peripheral edge 10d.
Back 2 including the tip surface 3a of the head 3
Continue to 2.
【００１１】尚、凹溝１４は本実施の形態に示すように
１つで構成したものに限定されることなく複数で構成さ
れていてもよく、複数の凹溝１４は工具本体２の長手方
向に沿って形成されていることが好ましい。この場合、
凹溝１４を複数で構成すればその位置に応じて受けるべ
き主分力と背分力の有無や大小によって凹溝１４の中心
軸Ｏに直交する断面積を増減して適宜設定できるから、
剛性低下を抑制する凹溝１４の設計が容易である。例え
ば、凹溝１４は工具本体の基端側から先端側に向けて、
容積が比較的大きい第一凹溝と比較的小さい第二凹溝が
順次形成されていてもよい。そのために例えば第一凹溝
の深さを深くしたり幅を広くしたり、第二凹溝の中心軸
線Ｏに向かう深さを浅くしたり溝の幅を狭くしたりして
もよい。The number of the grooves 14 is not limited to one as shown in the present embodiment, but may be a plurality of grooves. Is preferably formed along the line. in this case,
If the groove 14 is composed of a plurality of grooves, the sectional area perpendicular to the central axis O of the groove 14 can be appropriately set by increasing or decreasing the presence or magnitude of the main component force and the back component force to be received according to the position.
It is easy to design the concave groove 14 that suppresses a decrease in rigidity. For example, the concave groove 14 extends from the base end to the tip end of the tool body,
A first groove having a relatively large volume and a second groove having a relatively small volume may be sequentially formed. For this purpose, for example, the depth of the first groove may be increased or the width thereof may be increased, or the depth of the second groove toward the central axis O may be reduced or the width of the groove may be reduced.
【００１２】次に図１及び図５に示すシャンク部４にお
いて、その外周面１６には一対の平面部１７，１７が中
心軸Ｏを挟んで対向配置されている。これら平面部１
７，１７はシャンク部４を工作機械の主軸に回転不能に
固定するために円筒形状の外周面１６を切り欠いてシャ
ンク部４の全長に亘って形成されている。そしてシャン
ク部４の内部には、基端側端面４ａからヘッド部３の凹
溝１４近傍まで延びる例えば円柱状のめくら穴１８が穿
孔されており、このめくら穴１８は例えば中心軸Ｏと同
軸に形成されている。めくら穴１８の先端はヘッド部３
内に進入していてもよいが、少なくとも凹溝１４の底部
１４ａ近傍まで到達していないようにしてヘッド部３の
剛性低下を防止することが好ましい。尚、中心軸Ｏに略
直交する方向に見て、めくら穴１８は凹溝１４と重なら
ないように形成してもよい。Next, in the shank portion 4 shown in FIGS. 1 and 5, a pair of flat portions 17, 17 are opposed to each other on the outer peripheral surface 16 with the central axis O interposed therebetween. These plane parts 1
Numerals 7 and 17 are formed over the entire length of the shank portion 4 by notching the cylindrical outer peripheral surface 16 in order to fix the shank portion 4 to the main shaft of the machine tool so as not to rotate. In the inside of the shank portion 4, for example, a cylindrical blind hole 18 extending from the base end surface 4a to the vicinity of the concave groove 14 of the head portion 3 is bored. The blind hole 18 is coaxial with the central axis O, for example. Is formed. The tip of the blind hole 18 is the head 3
However, it is preferable that the rigidity of the head portion 3 is prevented from lowering by not reaching at least the vicinity of the bottom portion 14a of the concave groove 14. The blind hole 18 may be formed so as not to overlap with the concave groove 14 when viewed in a direction substantially perpendicular to the central axis O.
【００１３】図１に示すシャンク部４の長手方向の任意
位置でのＡ−Ａ線軸直交断面を示す図５において、めく
ら穴１８の断面積をＳａとし、めくら穴１８の周囲にお
けるシャンク部４の略リング状の肉厚部１９の断面積を
Ｓｂとする。ここでヘッド部３の構成を変えずにシャン
ク部４のめくら穴１８に関してシャンク部４の外径寸法
をその長さ方向に一定にして、シャンク部４の軸直交断
面におけるめくら穴１８の内径ｄ１を変化させて、それ
ぞれの中ぐりバイト１について切削加工試験を行った。
めくら穴１８の断面積Ｓａとシャンク部４の肉厚部１９
の断面積Ｓｂとの面積比Ｓａ／Ｓｂに対する固有振動数
比と工具本体２のたわみ（たわみ剛性）比について測定
すると図７に示す結果が得られた。In FIG. 5, which shows a cross section orthogonal to the line AA at an arbitrary position in the longitudinal direction of the shank portion 4 shown in FIG. 1, the sectional area of the blind hole 18 is Sa, and the shank portion 4 around the blind hole 18 is The cross-sectional area of the substantially ring-shaped thick portion 19 is Sb. Here, the outer diameter of the shank portion 4 is made constant in the longitudinal direction with respect to the blind hole 18 of the shank portion 4 without changing the configuration of the head portion 3, and the inner diameter d 1 of the blind hole 18 in the cross section orthogonal to the axis of the shank portion 4. And the cutting test was performed on each boring tool 1.
The cross-sectional area Sa of the blind hole 18 and the thick portion 19 of the shank portion 4
The measurement shown in FIG. 7 was obtained by measuring the natural frequency ratio and the deflection (flexure rigidity) ratio of the tool body 2 with respect to the area ratio Sa / Sb with respect to the cross-sectional area Sb.
【００１４】図７に示すグラフにおいて断面積比Ｓａ／
Ｓｂ＝０、即ちめくら穴１８の内径ｄ１＝０の中実のシ
ャンク部４の固有振動数比及びたわみ比をそれぞれ１と
する。そしてめくら穴１８の内径ｄ１を徐々に増大させ
ていき、めくら穴１８の断面積Ｓａを徐々に増大させこ
れに対応してシャンク部４の肉厚部１７の断面積Ｓｂを
徐々に減少させていった時の固有振動数比は、断面積比
Ｓａ／Ｓｂの増大につれて比例的に増大する。またシャ
ンク部４のたわみ比は断面積比Ｓａ／Ｓｂの増大につれ
て凹曲線を描いて増大するが、断面積比Ｓａ／Ｓｂが
１．３を越えると急激に増大して急激にたわみ剛性が損
なわれることになる。従って、シャンク部４のたわみ剛
性を確保するために断面積比Ｓａ／Ｓｂの上限を１．３
に設定することが好ましい。またビビリ振動を低減する
ためには固有振動数を大きく設定する必要があり、その
ためには中実のシャンクに対して固有振動数比が約１．
２以上あることが好ましく、これを達成する断面積比Ｓ
ａ／Ｓｂの下限値は０．２となる。従って、シャンク部
４におけるめくら穴１８とシャンク部４の肉厚部１９と
の任意位置での断面積比Ｓａ／Ｓｂを０．２〜１．３の
範囲に設定することが好ましい。尚、図１では、面積比
Ｓａ／Ｓｂはめくら穴１８の全長において一定である
が、０．２〜１．３の範囲で変化していても良い。In the graph shown in FIG. 7, the sectional area ratio Sa /
Sb = 0, that is, the natural frequency ratio and the deflection ratio of the solid shank 4 of the inner diameter d1 = 0 of the blind hole 18 are each set to 1. Then, the inner diameter d1 of the blind hole 18 is gradually increased, the sectional area Sa of the blind hole 18 is gradually increased, and the sectional area Sb of the thick portion 17 of the shank portion 4 is gradually reduced correspondingly. In this case, the natural frequency ratio increases proportionally as the cross-sectional area ratio Sa / Sb increases. The deflection ratio of the shank portion 4 increases in a concave curve as the cross-sectional area ratio Sa / Sb increases. However, when the cross-sectional area ratio Sa / Sb exceeds 1.3, the bending rigidity sharply increases and the bending rigidity deteriorates rapidly. Will be. Therefore, the upper limit of the sectional area ratio Sa / Sb is set to 1.3 in order to secure the bending rigidity of the shank portion 4.
It is preferable to set In order to reduce chatter vibration, it is necessary to set the natural frequency to a large value. For this purpose, the natural frequency ratio of the solid shank is about 1.
Preferably, there is at least two, and the cross-sectional area ratio S for achieving this is
The lower limit of a / Sb is 0.2. Therefore, it is preferable to set the cross-sectional area ratio Sa / Sb of the blind hole 18 in the shank portion 4 and the thick portion 19 of the shank portion 4 at an arbitrary position in the range of 0.2 to 1.3. In FIG. 1, the area ratio Sa / Sb is constant over the entire length of the blind hole 18, but may be changed in the range of 0.2 to 1.3.
【００１５】本実施の形態による中ぐりバイト１は上述
の構成を備えているから、図１において二点鎖線で示す
ワークＷを軸線Ｏ′回りに回転させ、これに対して図示
しない工作機械でシャンク部４を保持された中ぐりバイ
ト１のノーズ部１０ｅで切り込みつつワークＷの下穴を
切削加工する。この時、図６（ａ）に示すようにチップ
１１のノーズ部１０ｅで切削することによって生じる切
削力の主分力Ｆ1が作用する方向にはヘッド部３の背部
２２の肉厚が確保されるとともに、背分力Ｆ2が作用す
る方向には凹溝１４が形成されておらず、或いは仮に凹
溝１４が形成されていても先端側の深さの浅い領域が位
置するためにこの領域のヘッド部３の肉厚が比較的大き
いリブ部として確保されている。そのためにヘッド部３
の剛性を確保しつつ軽量化を達成できる。Since the boring tool 1 according to the present embodiment has the above-described configuration, the work W shown by the two-dot chain line in FIG. 1 is rotated around the axis O ', While cutting the shank portion 4 at the nose portion 10e of the boring tool 1 held, the pilot hole of the work W is cut. At this time, as shown in FIG. 6A, the thickness of the back portion 22 of the head portion 3 is ensured in the direction in which the main component force F1 of the cutting force generated by cutting at the nose portion 10e of the tip 11 acts. At the same time, the concave groove 14 is not formed in the direction in which the back force F2 acts, or even if the concave groove 14 is formed, a shallow region on the distal end side is located. The thickness of the portion 3 is secured as a relatively large rib portion. The head 3
Light weight can be achieved while ensuring the rigidity of the device.
【００１６】しかも本実施形態による中ぐりバイト１で
は、シャンク部４にめくら穴１８が形成されて中空形状
とされているためにシャンク部４を軽量化できる。この
時、シャンク部４の任意位置における軸直交断面での面
積比Ｓａ／Ｓｂが０．２〜１．３の範囲内であるからシ
ャンク部４を軽量化して固有振動数を増大できる上にシ
ャンク部４のたわみ剛性を確保できる。また面積比Ｓａ
／Ｓｂが０．２より小さいとシャンク部４の軽量化及び
固有振動数の増大を十分に達成できず、１．３より大き
いとたわみ剛性が低下して加工精度が悪化する。これに
よってヘッド部３だけでなくシャンク部４を大きく軽量
化して固有振動数の増大を図ることができ、中ぐりバイ
ト１１を含む機械系の固有振動数と切削抵抗による外力
の振動数との乖離を大きくして共振によるビビリ振動を
起き難くすることができる。また、ヘッド部３の外周面
３ｂにおいてチップポケット７及び第一凹部６と背部２
２の間に凹溝１４を形成することで、図６（ａ）〜
（ｄ）に示すように、切削力の主分力Ｆ1が作用する方
向に沿う肉厚を背部２２として大きく確保して剛性低下
を抑制している。換言すれば、主分力Ｆ1に直交する軸
Ｙに対する断面二次モーメントを保持しつつ余分な肉を
削り落とすことで、剛性低下を抑制しながらビビリ振動
を発生し難くしている。また、切削力の背分力Ｆ2を支
えるリブ部もヘッド部３の厚みとして確保されているた
め、背分力Ｆ2に沿う方向に作用する応力に対しても剛
性が確保され、この方向へのビビリ振動の発生も起き難
くしている。さらに、凹溝１４の先端をヘッド部３の先
端面３ａに開口させないように仕切部２１を形成するこ
とで先端領域の剛性低下も抑制できる。Moreover, in the boring tool 1 according to the present embodiment, the shank portion 4 can be reduced in weight because the blind hole 18 is formed in the shank portion 4 to be hollow. At this time, since the area ratio Sa / Sb in the cross section perpendicular to the axis at an arbitrary position of the shank portion 4 is in the range of 0.2 to 1.3, the shank portion 4 can be reduced in weight and the natural frequency can be increased. The flexural rigidity of the portion 4 can be secured. Also, the area ratio Sa
If / Sb is smaller than 0.2, it is not possible to sufficiently reduce the weight of the shank portion 4 and increase the natural frequency, and if it is larger than 1.3, the bending rigidity is reduced and the machining accuracy is deteriorated. As a result, not only the head portion 3 but also the shank portion 4 can be greatly reduced in weight and the natural frequency can be increased, and the difference between the natural frequency of the mechanical system including the boring tool 11 and the frequency of the external force due to the cutting resistance can be obtained. And chattering vibration due to resonance can be suppressed. Further, the chip pocket 7, the first concave portion 6 and the back portion 2 are formed on the outer peripheral surface 3 b of the head portion 3.
6 (a) to 6 (a)
As shown in (d), a large thickness along the direction in which the main component force F1 of the cutting force acts acts as the back portion 22 to suppress a decrease in rigidity. In other words, by cutting off excess meat while maintaining the second moment of area with respect to the axis Y orthogonal to the main component force F1, chattering vibration is hardly generated while suppressing rigidity reduction. Further, since the rib portion for supporting the back force F2 of the cutting force is also secured as the thickness of the head portion 3, the rigidity is secured against the stress acting in the direction along the back force F2. The occurrence of chattering vibration is also reduced. Further, by forming the partition 21 so that the tip of the concave groove 14 does not open to the tip end face 3a of the head 3, a decrease in rigidity in the tip region can be suppressed.
【００１７】以上のように本実施の形態の中ぐりバイト
１によれば、工具のたわみ剛性を維持しつつ固有振動数
を増大させて共振の発生を防止することでビビリ振動を
起き難くしているため、加工精度の向上およびチップ１
１の欠損防止を図ることができると同時に、工具本体２
の突き出し量を大きくとることができるようになり、よ
り深い下穴の内周面を高精度に仕上げ加工することが可
能になる。As described above, according to the boring tool 1 of the present embodiment, the natural frequency is increased while maintaining the bending stiffness of the tool to prevent occurrence of resonance, thereby making chatter vibration less likely to occur. To improve machining accuracy and insert 1
1 can be prevented, and at the same time, the tool body 2
Can be increased, and the inner peripheral surface of the deeper prepared hole can be finished with high precision.
【００１８】尚、本実施の形態では、ヘッド部３の第一
凹部６の先端側にチップポケット７を形成したものにつ
いて説明しているが、チップポケット７を形成しないも
のであっても構わない。またノーズ部１０ｅ及び外周刃
１０ｄに対向するヘッド部３の周方向反対側に凹溝１４
を形成した中ぐりバイト１であっても、従来の中ぐりバ
イトに比して工具剛性を維持しつつビビリ振動を起き難
くすることができる。また中ぐりバイト１のヘッド部３
には必ずしも凹溝１４を形成して軽量化する必要はな
く、シャンク部４にのみめくら穴１８を形成した構成を
採用してもよい。この場合、めくら穴１８をヘッド部３
内に延伸させてチップ取付座９に重ならない領域まで位
置させてもよい。上述の実施の形態では、中ぐりバイト
１にスローアウェイチップ１０を配設したが、本発明は
このような構成に限定されることなくろう付けタイプの
切刃やソリッドタイプの切刃等を有する切削工具にも採
用できる。しかもこれら切削工具の材質は何でも良く、
例えば超硬合金で構成されていてもよいし、或いはヘッ
ド部とシャンク部とで別材質でもよく例えばヘッド部を
スチールとしてシャンク部を超硬合金にしてもよい。本
発明による中ぐりバイト１に油穴を形成する場合には、
めくら穴１８を油穴として兼用しても良く、この場合に
はめくら穴１８の先端から切刃近傍の開口部までめくら
穴１８より小径の油穴で連通して構成してもよい。その
際、もちろん小径の油穴は凹溝１４に連通しないことが
好ましく両者の間にヘッド部３の剛性を低下させない程
度の適宜の肉厚が存在することが更に好ましい。尚、本
発明は上述の実施の形態で説明した中ぐりバイト１に限
定されることなく他の各種のバイト等の旋削工具や転削
工具等の切削工具に採用できる。In the present embodiment, the case where the tip pocket 7 is formed on the tip side of the first concave portion 6 of the head portion 3 is described, but the tip pocket 7 may not be formed. . Further, a concave groove 14 is formed on the opposite side of the head portion 3 in the circumferential direction opposite to the nose portion 10e and the outer peripheral blade 10d.
Even if the boring tool 1 is formed, chatter vibration can be suppressed while maintaining the tool rigidity as compared with the conventional boring tool. In addition, head part 3 of boring tool 1
It is not always necessary to form the concave groove 14 to reduce the weight, and a configuration in which the blind hole 18 is formed in the shank portion 4 may be adopted. In this case, the blind hole 18 is inserted into the head 3
It may be extended inward and positioned to a region that does not overlap with the chip mounting seat 9. In the above-described embodiment, the throw-away tip 10 is disposed on the boring tool 1. However, the present invention is not limited to such a configuration, and has a brazing-type cutting edge, a solid-type cutting edge, and the like. Can also be used for cutting tools. Moreover, these cutting tools can be made of any material,
For example, the head portion and the shank portion may be made of cemented carbide, or the head portion and the shank portion may be made of different materials. For example, the head portion may be made of steel and the shank portion may be made of a hard metal. When an oil hole is formed in the boring tool 1 according to the present invention,
The blind hole 18 may also be used as an oil hole. In this case, the blind hole 18 may be configured to communicate from the tip of the blind hole 18 to an opening near the cutting edge with an oil hole smaller in diameter than the blind hole 18. At this time, it is preferable that the small-diameter oil hole does not communicate with the concave groove 14, and it is more preferable that the oil hole has an appropriate thickness between the two so as not to reduce the rigidity of the head portion 3. The present invention is not limited to the boring tool 1 described in the above embodiment, but can be applied to other various turning tools such as a cutting tool and cutting tools such as a rolling tool.
【００１９】[0019]
【発明の効果】上述のように本発明に係る切削工具は、
シャンク部の中心軸に直交する断面におけるめくら穴の
断面積とシャンク部の肉厚部の断面積との比が０．２〜
１．３の範囲に設定されているから、シャンク部の質量
を軽量化できると共にたわみ剛性を十分確保することが
でき、切削時のビビリ振動と工具本体のたわみを抑えて
加工精度を向上できる。As described above, the cutting tool according to the present invention has the following features.
The ratio of the cross-sectional area of the blind hole to the cross-sectional area of the thick part of the shank in a cross section orthogonal to the central axis of the shank is 0.2 to
Since it is set in the range of 1.3, the mass of the shank portion can be reduced in weight and the bending rigidity can be sufficiently secured, and the chatter vibration during cutting and the bending of the tool body can be suppressed to improve the processing accuracy.
【００２０】また工具本体のヘッド部に切刃を備え、ヘ
ッド部には切刃のすくい面につながるチップポケットと
切刃の逃げ面につながる背部との間の外周面に凹溝が形
成されているから、凹溝によってヘッド部を軽量化すれ
ばシャンク部を含めて工具本体全体を軽量化できて固有
振動数を著しく増大できて外力即ち切削抵抗による振動
数との乖離を大きくして共振によるビビリ振動を効果的
に抑制できる。しかも凹溝の位置は切刃に対して周方向
反対側の対向する外周面であるから、切屑を走行させる
切刃のすくい面の領域や切刃の逃げ面を含む領域であっ
て切削力の主分力を受ける背部から外れているために切
屑排出性を妨げたりヘッド部の剛性低下を来すことがな
い。また凹溝は、工具本体の先端面と仕切られているか
ら、ヘッド部の先端の剛性低下を抑制できる。Further, a cutting blade is provided in a head portion of the tool body, and a concave groove is formed in an outer peripheral surface between a tip pocket connected to a rake face of the cutting blade and a back portion connected to a flank of the cutting blade. Therefore, if the head part is reduced in weight by the concave groove, the entire tool body including the shank part can be reduced in weight, the natural frequency can be significantly increased, and the deviation from the external force, that is, the frequency due to the cutting resistance, is increased, and the resonance is caused. Chatter vibration can be effectively suppressed. Moreover, since the position of the concave groove is the outer peripheral surface opposite to the cutting edge in the circumferential direction, it is the area of the rake face of the cutting blade for running the chips and the area including the flank of the cutting blade and the cutting force Since it is separated from the back receiving the main component force, there is no hindrance to chip discharge and no reduction in rigidity of the head. In addition, since the concave groove is partitioned from the distal end surface of the tool main body, a decrease in rigidity at the distal end of the head portion can be suppressed.
【図１】 本発明の実施の形態による中ぐりバイトを
チップのすくい面方向から見た平面図である。FIG. 1 is a plan view of a boring tool according to an embodiment of the present invention as viewed from a rake face direction of a chip.
【図２】 図１に示す中ぐりバイトを外周刃方向から
見たヘッド部の拡大側面図である。FIG. 2 is an enlarged side view of a head portion of the boring tool shown in FIG. 1 as viewed from an outer peripheral blade direction.
【図３】 図１に示す中ぐりバイトを先端方向から見
た拡大正面図である。FIG. 3 is an enlarged front view of the boring tool shown in FIG. 1 as viewed from a front end direction.
【図４】 中ぐりバイトのヘッド部を凹溝方向から見
た拡大側面図である。FIG. 4 is an enlarged side view of a head portion of the boring tool as viewed from a groove direction.
【図５】 図１に示す中ぐりバイトのシャンク部のＡ
−Ａ線拡大断面図である。FIG. 5 shows the A of the shank portion of the boring tool shown in FIG.
FIG. 4 is an enlarged cross-sectional view taken along a line A.
【図６】 図４に示すヘッド部について、（ａ）はＢ
−Ｂ線断面図、（ｂ）はＣ−Ｃ線断面図、（ｃ）は同図
のＤ−Ｄ線断面図、（ｄ）は同図のＥ−Ｅ線断面図であ
る。6A is a diagram illustrating a head section shown in FIG. 4; FIG.
FIG. 2B is a sectional view taken along line B, FIG. 2B is a sectional view taken along line CC, FIG. 2C is a sectional view taken along line DD in FIG.
【図７】 実施の形態による中ぐりバイトのシャンク
部の断面積比と固有振動数比及びたわみ比の関係を示す
図である。FIG. 7 is a diagram showing a relationship between a sectional area ratio of a shank portion of a boring tool, a natural frequency ratio, and a deflection ratio according to the embodiment.
１ 中ぐりバイト ２ 工具本体 ３ ヘッド部 ４ シャンク部 ７ チップポケット １４ 凹溝 １８ めくら穴 １９ 肉厚部 DESCRIPTION OF SYMBOLS 1 Boring tool 2 Tool body 3 Head part 4 Shank part 7 Tip pocket 14 Concave groove 18 Blind hole 19 Thick part
Claims (3)
ンク部の中心軸に沿って延びる中空のめくら穴を形成し
てなる切削工具において、 前記シャンク部の中心軸に直交する断面におけるめくら
穴の断面積と前記シャンク部の肉厚部の断面積との比が
０．２〜１．３の範囲に設定されていることを特徴とす
る切削工具。1. A cutting tool having a hollow blind hole extending along a central axis of a shank portion inside a shank portion of a tool body, wherein the blind hole has a cross section orthogonal to the central axis of the shank portion. A cutting tool, wherein a ratio of a cross-sectional area to a cross-sectional area of a thick portion of the shank portion is set in a range of 0.2 to 1.3.
記ヘッド部には前記切刃のすくい面につながるチップポ
ケットと前記切刃の逃げ面につながる背部との間の外周
面に凹溝が形成されていることを特徴とする請求項１記
載の切削工具。2. A tool body having a head portion provided with a cutting edge, wherein the head portion has a groove formed on an outer peripheral surface between a tip pocket connected to a rake face of the cutting edge and a back portion connected to a flank of the cutting edge. The cutting tool according to claim 1, wherein the cutting tool is formed.
仕切られていることを特徴とする請求項２記載の切削工
具。3. The cutting tool according to claim 2, wherein the concave groove is partitioned from a front end surface of the tool main body.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30776299A JP2001121307A (en) | 1999-10-28 | 1999-10-28 | Cutting tool |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30776299A JP2001121307A (en) | 1999-10-28 | 1999-10-28 | Cutting tool |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2001121307A true JP2001121307A (en) | 2001-05-08 |
Family
ID=17972976
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP30776299A Withdrawn JP2001121307A (en) | 1999-10-28 | 1999-10-28 | Cutting tool |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2001121307A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7140713B2 (en) | 2002-10-28 | 2006-11-28 | Seiko Epson Corporation | Recording apparatus and communication method |
| CN102205427A (en) * | 2010-03-31 | 2011-10-05 | 日本特殊陶业株式会社 | Cutting tool for boring |
| CN102672209A (en) * | 2012-05-14 | 2012-09-19 | 华中科技大学 | Cutter with function of decoupling temperature of turning area |
| JP2013188847A (en) * | 2012-03-14 | 2013-09-26 | Mitsubishi Materials Corp | Hard alloy cutting tool |
-
1999
- 1999-10-28 JP JP30776299A patent/JP2001121307A/en not_active Withdrawn
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7140713B2 (en) | 2002-10-28 | 2006-11-28 | Seiko Epson Corporation | Recording apparatus and communication method |
| CN102205427A (en) * | 2010-03-31 | 2011-10-05 | 日本特殊陶业株式会社 | Cutting tool for boring |
| JP2011224770A (en) * | 2010-03-31 | 2011-11-10 | Ngk Spark Plug Co Ltd | Cutting tool for boring |
| KR101340149B1 (en) | 2010-03-31 | 2013-12-10 | 니혼도꾸슈도교 가부시키가이샤 | Cutting tool for boring |
| JP2013188847A (en) * | 2012-03-14 | 2013-09-26 | Mitsubishi Materials Corp | Hard alloy cutting tool |
| CN102672209A (en) * | 2012-05-14 | 2012-09-19 | 华中科技大学 | Cutter with function of decoupling temperature of turning area |
| CN102672209B (en) * | 2012-05-14 | 2014-03-26 | 华中科技大学 | Cutter with function of decoupling temperature of turning area |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A300 | Withdrawal of application because of no request for examination |
Free format text: JAPANESE INTERMEDIATE CODE: A300 Effective date: 20070109 |