JP2560114C

JP2560114C -

Info

Publication number: JP2560114C
Authority: JP
Original assignee: Kitagawa Iron Works Co Ltd
Current assignee: Kitagawa Iron Works Co Ltd
Publication date: 1998-09-03

Description

【発明の詳細な説明】［産業上の利用分野］本発明は、工作機械に用いるチャックに関するものであり、近年の高速回転化
傾向に伴う高回転域においても、強大な把握力と高い把握精度の得られる機能を
備えたチャックに関するものである。［従来の技術］従来の中実チャック構造は、ボディの半径方向内方部位に相当するジュウの内
方部分にプランジャと噛合する噛合手段を備えるものであり、第１図乃至第４図
の如きである。さらに中空チャック構造は、ボディの軸線方向後方部位で且つ半
径方向内方部位に相当するジョウの後方内方部分にプランジャと噛合する噛合手
段を備えるものであり、例えば特開昭５５−１０６７０７号公報記載のＦig１乃
至Ｆig４図及び実開昭５３−９９０８１号のマイクロフィルム記載の如きである
。しかし、前者及び後者いずれの噛合手段においても、ジョウ側の噛合部強度と
プランジャ側の噛合部強度とには著しい差があり、この力学的な強度差を解消す
ることは、構造的制限から困難であるとされていた。しかも、この力学的な強度差は、把握力が増大するに伴ってさらに拡大する傾
向にあることから高回転域において特に問題となる課題であった。［発明が解決しようとする課題］本発明は、係る従来のチャックの欠点をみごとに解決するものであり、噛合手
段の構造を構造力学的側面から究明することによって、特にプランジャ側の噛合
部強度を向上させ、且つプランジャとボディとを合理的な形状の組合せとなし、
歪の極めて少ない強力なプランジャ及び剛性に影響されないボディを得ることに
主眼がある。［課題を解決するための手段］しかるに、本発明は、後述する如き特殊なボディの構造及び特殊なジョウの構
造ならびに特殊なプランジャの構造になすと共に、特にジョウ及びプランジャの
噛合手段を力学的に合理性のある構造となさしめたものであり、その特徴とする
ところは、ボディ中心穴および放射方向へ複数の案内溝を有するボディと、該ボ
ディ中心穴を軸線方向前方・後方へ摺動移動し、前記案内溝に対応する複数のウ
ェッジ溝を備えるひとつのプランジャと、該プランジャの摺動移動に連動しボデ
ィの半径方向内方・外方へ摺動移動する複数のジョウとからなるチャックが、以
下のように構成されている。すなわち、（ア）前記プランジャは、各ウェッジ溝５が断面逆Ｔ字形の空間に形成されるよ
うな対の顎部（Ｖ）を備えていること、（イ）前記ボディに設けた複数のジョウの各案内溝には、その溝底部位にスロッ
ト溝（１１）が設けられ、該スロット溝（１１）の幅は、前記対の顎部（Ｖ）の
夫々が曲げ力の作用で変形しながら破損する際における破損し易い部位よりも狭
い幅に形成され、且つ該スロット溝（１１）がボディの半径方向外方寄りに適量
の肉厚部（Ｗ）を残して形成されていること、（ウ）前記ジョウの後方に突出部（１２）を備え、該突出部がひとつの楔部材（
５０）と該楔部材に直交しこれよりも幅が狭い補強部材（６０）とから形成されていること、（エ）前記各ジョウの楔部材（５０）の夫々が、プランジャに設けた複数のウェ
ッジ溝（５）のいずれかと噛合する構造になされていること、（オ）前記補強部材（６０）が、スロット溝（１１）に収容される部分を備える
形状になされていること、及び、（カ）前記破損し易い部位の外周面（Ｇ）が、曲げ力の作用によって変形するに
際して、スロット溝（１１）の近傍のボディ中心穴の内周面（Ｆ）で支え得る保
持構造になされていることにある。［作用］第７図と第８図を用いてその作用を説明すると、プランジャ４の軸線方向作用
力で被加工物を把握したときに発生するジョウ２の突出部１２における負荷の分
力は、面圧負荷分力と曲げ負荷分力とに分けられ、一方の面圧負荷をもっぱらに
ひとつの楔部材５０が荷担するものとなし、他方の曲げ負荷をもっぱらに補強部
材６０が荷担するものとなすのである。係るジョウ２の突出部１２の形状となし、加えて前記負荷分力の分力荷担構造
を用いることによって、プランジャ４の逆Ｔ字形ウェッジ溝を形どる張り出し部
材がはじめて片振り荷重のみを荷担すればよいものとなるのである（従来形状の
ジョウは、両振り荷重を荷担しなければならない欠点があった）。［実施例］本発明に係るチャックの一例を第５図乃至第９図を用いて詳述する。第５図は三つ爪チャックの縦断面図、第６図はそのボディ１を斜め方向から見
た拡大部分図、第７図はマスタージョウの２の斜視図、第８図は第５図のＹ−Ｙ
′線切断拡大図、第９図はプランジャ４の斜視図である。第６図に示す如く、ボディ１には矢印Ｚ方向の内方から半径方向の外方へ向け
てマスタ−ジョウ２を嵌装するための案内溝１０が３方向等分（１方向のみ図示
する）に設けられているのほか、案内溝１０の溝底には該溝幅よりも狭く且つ半
径方向外方寄りに適量肉厚部Ｗを残す一定長さＫで幅Ａのスロット溝１１が設け
られており、該スロット溝１１には第７図に示すマスタ−ジョウ２の突出部１２
を構成する補強部材６０の一部が収納されるようになされている。この際、該スロット溝幅Ａは、第８、９図示のようにプランジャ４のウェッジ
溝の外周方向空間５ａの幅Ｂと近似的に等しくなすことが望ましい。他方前記外
周面Ｇと前記内周面Ｆとの間隙は、プランジャ４が軸線方向に摺動可能な範囲で
最小に設定しチャックの把握精度を保持するものである。以上のチャック構造において、第７図に示す如くマスタ−ジョウ２には、その
後方内方寄りに突出部であるところの逆Ｔ字形の突出部１２が設けてある。該突
出部１２は、第９図に示すプランジャ４のウェッジ溝５と噛合するときに楔作用
を発生する楔部材５０と、該楔部材部材に直交しこれを力学的に補強する補強部
材６０とから形成されている。さらに切断端面形状Ｔ字形に形成されていて、楔
部材５０はもっぱらに噛合時の面圧負荷を荷担し、補強部材６０はもっぱらに噛
合時の曲げ負荷を荷担する。前記ウェッジ溝５ｄは逆Ｔ字形の空間をなし、この
空間は、プランジャの半径方向に伸びプランジャの外周面に開口する半径方向空
間５ａと、この空間５ａと直交する横方向空間５ｂからなり、前記半径方向空間
５ａ内を補強部材６０が伸び、前記横方向空間５ｂ内に楔部材５０が収納されて
いる。しかるに、要求される補強部材６０の形状は、噛合時における曲げ負荷に有効
なるようにその断面係数Ｚが大なるものであること、即ち力学的計算式で説明す
れば、幅をＣとし、突出部１２のジョウの長手方向の丈長をＬとしたとき、Ｚ＝
ＣＬ²／６（Ｃ、Ｌは第７図示）におけるＬを最大限に大きくすることである。また、マスタージョウ２における突出部１２の丈長Ｌ（楔部材５０の厚さに補
強部材の高さを加えた長さ）の最大長さは、マスタージョウ２の長さ１の半分程
度にされる。本実施例に用いるチャックでは、ボディ１の半径方向内方寄りに形成したスロ
ット溝１１に収容される部分を備える形状の補強部材６０となすことにより、前
述した寸法Ｌを極めて大きくできる工夫をなしたものである。前記突出部１２の
補強部材６０のジョーの長手方向の丈長Ｌが突出部の突出方向に向かうに従って
漸減する形状に形され、曲げモーメントに丈長Ｌがほぼ対応するようになってい
る。しかしながら、補強部材６０の外方端面の形状を第７図の如き直線とせずに
、加工が困難であることを別にすれば、力学的に合理性のある曲げモーメント線図曲線に類似させるとよい。これに対し、特開昭５５−１０６７０７合公報記載の発明に係る楔かぎ片１０
の形状は、楔面１０ａとうね状隆起１０ｂとをもつ断面凸状に形成されたもので
あり、楔かぎ片１０の半径方向厚さを大きくすることで前述の曲げ負荷を荷担す
るものである。しかるに、曲げ負荷を荷担するに最も有効なうね状隆起１０ｂの
隆起量が激減することから、強力な把握力は得られないものとなるのである。従って、本実施例に関する第７図示のマスタ−ジョウと比べたとき、その曲げ
負荷は断然に小さなものとなるのである。把握力を従来にない、より強力なチャックとなすためのもうひとつの工夫につ
いて、プランジャの構造を基にし説明する。先ず、従来のチャックにおけるプランジャ構造について第１図乃至第４図を用
い、詳しく説明する。第１図は三つ爪チャックの上部縦断面図であって、第１３図に示す如くボディ
１′の半径方向に３等分の放射線状案内溝１０′を設け、該案内溝１０′に第２
図示のマスタ−ジョウ２′が摺動自在に嵌挿される。そして、マスタ−ジョウ２
′の前方（ボディ１′の前方Ｒ側及びＳ側）にはトップジョウ３′が図示しない
ボルトで固着され、またボディ１′中心の穴にはプランジャ４′が軸線方向の摺
動を自在になし嵌挿されている。しかして、プランジャ４′の外周にも第３図に示す如き３方向等分（１方向の
み図示する）にウェッジ溝５′が設けてあり、マスタ−ジョウ２′の内方に設け
られている突出部２′ａと噛合する。該噛合状態の詳細が第１図のＸ−Ｘ′線切
断拡大図である第４図に示されている。係るジョウの内方部分に噛合手段を備えた構造のチャックは、以下の作用的欠
陥を持っている。今トップジョウ３′で図示しない被加工物の外径を把握するための作動を行う
と、マスタ−ジョウ２′の突出部２′ａには、矢印Ｐなる力が半径方向の外方へ
向けて作用し、この力Ｐが顎部４′ｂへ負荷され、該負荷の作用によりプランジ
ャ４′の逆Ｔ字形ウェッジ溝４′ａを形どる張り出し部材には、ボディ１′の穴
との接触が離合する部分Ｑを基点として曲げモ−メントＭが矢印方向に作用する。しかして更に作用力Ｐが増大すると該部分は弾性変形に伴う応力の集中を受け
ジグザグ線６の如き破損が進行する。他方トップジョウ３′で図示しない被加工物の内径を把握するための作動を行
うと、マスタ−ジョウ２′の突出部２′ａには、矢印Ｐに反対する方向の力が半
径方向内方へ作用し、この力の作用により前記の張り出し部材には、曲げモ−メ
ントＭが矢印方向に反対する方向へ作用する。即ち、顎部４′ｂには矢印Ｐ方向の力及び矢印Ｐに反対する方向の力が共に負
荷されるのである。別言すれば、力Ｐの負荷に対してウェッジ溝４′ａを形どる
張り出し部材は常に両振り荷重を荷担しなければならない欠点がある。係る顎部４′ｂへの力の負荷は、上記例における内方部分に噛合手段を備えた
ジョウの構造のみならず、後方内方部分に噛合手段を備えたジョウの構造（例え
ば特開昭５５−１０６７０７号公報のＦｉｇ１乃至Ｆｉｇ２及び実開昭５３−９
９０８１号のマイクロフィルム）においても、全く同様である。叙上の従来チャック構造に対し本実施例のものは、第８図示の如く、プランジ
ャ４の顎部外周面Ｇをボディ１の穴の内周面Ｆで支える構造となし、前記曲げモ
ーメントＭの作用を阻止する工夫によって前記ジグザグ線６による破損を完全に
防止するものである。［作用］本実施例は以上の如き構造のチャックを用い、図示しないシリンダの作動によ
ってプランジャ４をボディの軸線方向前方・後方へ摺動移動させる。この摺動移
動に伴うプランジャ４の軸線方向作用力で各トップジョウ３を同時に作動させ被
加工物の外径を把握すると、夫々のマスタ−ジョウ２の突出部１２には半径方向
の内方へ向けて負荷が発生する。しかして該負荷は、突出部１２の楔部材５０を
押圧破損する作用分力（面圧負荷分力）と、突出部１２の補強部材６０を曲げ破
損する作用分力（曲げ負荷分力）とに分かれて荷担される。なお、この把握と反対に、被加工物の内径を把握するときは、前記突出部１２
の半径方向の外方へ向けての負荷が発生し、前記外径把握と異なる逆方向への面
圧負荷分力と曲げ負荷分力とに分かれて荷担される。よって、前記楔部材５０は、外径把握と内径把握とで荷担方向が異なる両振り荷重による分力荷担機能になされている。次にプランジャ４側における力学的な強度を検討してみると、該プランジャ４
は前述の面圧負荷分力の反力をウェッジ溝５を形どる張り出し部材における顎部
Ｖの横方向空間５ｂを画する面をなす顎面Ｔで受け止める構造になされているこ
とからこの面圧負荷分の反力に充分耐え得る寸法の形状になされている。しかし
、さらに被加工物の把握力を増大させ荷担する負荷を増加させると前記張り出し
部材は、第４図に示す如き矢印Ｐ方向の曲げモ−メントＭを受け半径方向外方へ
の弾性変形により曲げが発生する。係る場合には、顎部Ｖの外周面Ｇをスロット
溝１１近傍の内周面Ｆで支えることから、顎部Ｖの曲げ応力は増加せず圧縮応力
として荷担され第４図のジグザグ線６の如き破損が進行することは全くなくなる
のである。しかるに、このように顎部Ｖの外周面Ｇを支える面は、プランジャ４
の移動範囲全域で形成される構造になされることが望ましいのは勿論のことであ
る。他方、トップジョウ３で被加工物の内径を把握すると、突出部１２の楔部材５
０には半径方向の外方へ向けての負荷が発生する。しかして前述の説明から明ら
かなとおり、プランジャ４の前記顎部Ｖへの面圧負荷分力は、全く負荷されない
ことから係る分力荷担の必要がない。即ち前記張り出し部材は、従来の両振り荷
重と全く異なる片振り荷重による分力荷担機構となるものである。［他の実施例］他の実施例を説明するに、プランジャ４の顎部Ｖの外周面Ｇは、第９図に示す
如くウェッジ溝５の端縁部まで円弧に形成されスロット溝１１近傍の内周面Ｆと
充分に接触する面積大になされるものが望ましい。若し前記マスタ−ジョウ２と
の噛合関係からこの円弧の一部である顎部の互いに対向する外周前方隅端面を切
削する場合でも、第１０図に示す如くウェッジ溝の半径方向空間５ａの幅を含む
切削幅Ｈは、マスタ−ジョウ２の楔部材５０の幅Ｄよりも小さくするのが好まし
く、Ｈ＜Ｄであれば前記円弧の例と同様な作用効果が得られるものとなる。また、プランジャのウェッジ溝形状は、第８図示例の如き単なる逆Ｔ字形をな
すもののほかに、第１１図に示す形状の如くウェッジ溝の横方向空間５ｂの横方
向両端部にヌスミ空間Ｎを形成し、集中応力の分散を図り顎部Ｖの横方向空５ｂを画する面をなす顎面Ｔへ作用する力による局部破損を防止するとか、また第１
２図に示す形状の如く前記顎面Ｔをウェッジ溝５の中心線に向け厚さが漸減する
直線或いは曲線からなる屋根形の傾斜面に形成し、負荷である曲げモ−メントＭ
に対応した合理的な形状になすとかして、より一層の強度的な安全度を高めるよ
うになすことができる。［発明の効果］本発明は、叙上のような構成になされていることから、プランジャにおいては
、力学的に弱いウェッジ溝を形どる張り出し部材をボディの剛性を活用して補強
するようにして解決し、従来にない強力な且つ把握精度の良好なものが得られる
のであり、ボディにおいては、半径方向の外方寄りに適量な肉厚部を残すスロッ
ト溝を形成する工夫により何等剛性に影響されないものとなるのである。さらに
これらを力学的に合理性のある組合せに構成することにより得られたチャック構
造は、従来のものに比べ力学的な強度の均衡が図られており、大幅に剛性が向上
し、強力な超把握力が得られ、把握精度の飛躍的な向上が図られるものとなるの
である。さらにボディのスロット溝にジョウの補強部材が収容できる構造は、チャック
のボディ厚さを極めて薄くすることができるほか、プランジャの軸線方向移動量
を大きくできることから、半径方向へのジョウ移動量が大きくなる著効を奏する
のである。そしてジョウの突出部形状を工夫したことによって得られた把握力の
向上は、特に切削速度のスピ−ドアップと、このスピ−ドアップに伴なう精度の
低下防止に著効がある。しかも軽量化されたジョウの突出部は、高回転域におけ
る慣性力の減少にも優れた性能を発揮する著効を奏するものである。Description: TECHNICAL FIELD The present invention relates to a chuck used for a machine tool, and has a strong gripping force and a high gripping accuracy even in a high rotation range due to a recent high-speed rotation tendency. The present invention relates to a chuck having a function of obtaining the above. [Prior Art] A conventional solid chuck structure has a meshing means for meshing with a plunger in an inner portion of a jaw corresponding to a radially inner portion of a body, as shown in FIGS. 1 to 4. It is. Further, the hollow chuck structure has a meshing means for meshing with a plunger at a rear inner portion of the jaw corresponding to an axially rear portion and a radially inner portion of the body. For example, JP-A-55-106707 discloses the hollow chuck structure. As shown in FIG. 1 to FIG. 4 described in the description and the microfilm described in Japanese Utility Model Application Laid-Open No. 53-99081. However, in both the former and the latter engagement means, there is a remarkable difference between the engagement strength on the jaw side and the engagement strength on the plunger side, and it is difficult to eliminate this mechanical strength difference due to structural limitations. It was supposed to be. In addition, this mechanical strength difference is a problem that is particularly problematic in a high rotation speed region because it tends to further increase as the gripping force increases. [Problems to be Solved by the Invention] The present invention solves the drawbacks of the conventional chuck, and the strength of the meshing portion, particularly on the plunger side, is determined by investigating the structure of the meshing means from the structural mechanical side. The plunger and the body with a reasonable combination of shapes,
The focus is on obtaining a strong plunger with very little distortion and a rigidly insensitive body. Means for Solving the Problems According to the present invention, a special body structure, a special jaw structure, and a special plunger structure as described later are provided, and in particular, the jaw and the engagement means of the plunger are dynamically provided. It has a rational structure, and its features are a body having a body center hole and a plurality of guide grooves in the radial direction, and sliding movement of the body center hole forward and backward in the axial direction. A chuck comprising a plunger having a plurality of wedge grooves corresponding to the guide grooves, and a plurality of jaws sliding inward and outward in the radial direction of the body in conjunction with the sliding movement of the plunger. , Are configured as follows. (A) the plunger includes a pair of jaws (V) such that each wedge groove 5 is formed in a space having an inverted T-shaped cross section; (b) a plurality of jaws provided on the body. Each guide groove is provided with a slot groove (11) at a groove bottom portion, and the width of the slot groove (11) is such that each of the pair of jaws (V) is deformed by the action of a bending force. (B) the slot groove (11) is formed to have a smaller width than a portion that is easily damaged when the breakage occurs, and the slot groove (11) is formed leaving an appropriate amount of a thick portion (W) toward the outside in the radial direction of the body; C) a projection (12) is provided behind the jaw, and the projection is a single wedge member (
50) and a reinforcing member (60) orthogonal to the wedge member and having a smaller width than the wedge member. (D) Each of the wedge members (50) of each jaw includes a plurality of wedge members provided on the plunger. (E) the reinforcing member (60) is formed in a shape including a portion accommodated in the slot groove (11); F) The outer peripheral surface (G) of the fragile portion is supported by the inner peripheral surface (F) of the body center hole near the slot groove (11) when deformed by the action of bending force. Is to be. [Operation] The operation will be described with reference to FIGS. 7 and 8. The component force of the load on the protrusion 12 of the jaw 2 generated when the workpiece is grasped by the axial acting force of the plunger 4 is as follows. A surface load load component and a bending load component force, wherein one surface pressure load is exclusively carried by one wedge member 50 and the other bending load is exclusively carried by the reinforcing member 60. It is. By using the shape of the protruding portion 12 of the jaw 2 and using the component load bearing structure of the load component, the projecting member that forms the inverted T-shaped wedge groove of the plunger 4 bears only the pulsating load for the first time. The conventional jaw has the drawback that it must carry a swing load. Example An example of the chuck according to the present invention will be described in detail with reference to FIGS. FIG. 5 is a longitudinal sectional view of the three-jaw chuck, FIG. 6 is an enlarged partial view of the body 1 viewed from an oblique direction, FIG. 7 is a perspective view of the master jaw 2, and FIG. Y-Y
9 is a perspective view of the plunger 4. As shown in FIG. 6, a guide groove 10 for fitting the master jaw 2 from the inside in the arrow Z direction to the outside in the radial direction is equally divided into three directions in the body 1 (only one direction is shown). In addition to the above, a slot groove 11 having a constant length K and a width A is provided at the bottom of the guide groove 10 at a groove bottom which is narrower than the groove width and leaves an appropriate amount of thick portion W outward in the radial direction. The protruding portion 12 of the master jaw 2 shown in FIG.
The part of the reinforcing member 60 that constitutes is stored. At this time, the slot groove width A is desirably approximately equal to the width B of the outer circumferential space 5a of the wedge groove of the plunger 4, as shown in FIGS. On the other hand, the gap between the outer peripheral surface G and the inner peripheral surface F is set to a minimum value within a range in which the plunger 4 can slide in the axial direction, thereby maintaining the gripping accuracy of the chuck. In the above chuck structure, as shown in FIG. 7, the master jaw 2 is provided with an inverted T-shaped projecting portion 12 which is a projecting portion toward the rear inward. The projecting portion 12 has a wedge member 50 that generates a wedge action when engaged with the wedge groove 5 of the plunger 4 shown in FIG. 9, and a reinforcing member 60 that is orthogonal to the wedge member member and mechanically reinforces the wedge member. Is formed from. Further, the cut end surface is formed in a T-shape, and the wedge member 50 exclusively bears the surface pressure load at the time of engagement, and the reinforcing member 60 exclusively bears the bending load at the time of engagement. The wedge groove 5d forms an inverted T-shaped space, which comprises a radial space 5a extending in the radial direction of the plunger and opening on the outer peripheral surface of the plunger, and a lateral space 5b orthogonal to the space 5a. The reinforcing member 60 extends in the radial space 5a, and the wedge member 50 is housed in the lateral space 5b. However, the required shape of the reinforcing member 60 is such that its sectional modulus Z is large so as to be effective for the bending load at the time of meshing. When the length in the longitudinal direction of the jaw of the part 12 is L, Z =
CL ^2/6 (C, L seventh shown) is to increase maximize L in. The maximum length L of the protruding portion 12 of the master jaw 2 (the length obtained by adding the height of the reinforcing member to the thickness of the wedge member 50) is set to about half of the length 1 of the master jaw 2. You. In the chuck used in the present embodiment, the reinforcing member 60 having a portion to be accommodated in the slot groove 11 formed inward in the radial direction of the body 1 is formed, so that the above-described dimension L can be made extremely large. It was done. The length L in the longitudinal direction of the jaw of the reinforcing member 60 of the protruding portion 12 is shaped so as to gradually decrease as it goes in the protruding direction of the protruding portion, and the length L substantially corresponds to the bending moment. However, the shape of the outer end face of the reinforcing member 60 should not be a straight line as shown in FIG. 7, but should be similar to a mechanically reasonable bending moment diagram curve, except for the difficulty of machining. . On the other hand, a wedge hook 10 according to the invention described in Japanese Patent Application Laid-Open No. 55-106707.
Is formed in a convex cross section having a wedge surface 10a and a ridge-shaped ridge 10b, and bears the above-mentioned bending load by increasing the radial thickness of the wedge key piece 10. . However, since the amount of the ridge 10b most effective for carrying the bending load is drastically reduced, a strong grasping force cannot be obtained. Therefore, when compared with the master jaw shown in FIG. 7 relating to the present embodiment, the bending load is much smaller. Another device for achieving a stronger chuck than ever before will be described based on the structure of the plunger. First, a plunger structure in a conventional chuck will be described in detail with reference to FIGS. FIG. 1 is a vertical sectional view of the upper part of the three-jaw chuck. As shown in FIG. 13, three radial guide grooves 10 'are provided in the radial direction of the body 1'. 2
The illustrated master jaw 2 'is slidably inserted. And Master-Jaw 2
The top jaw 3 'is fixed to the front of the body 1' (the front R side and the S side of the body 1 ') with bolts (not shown), and a plunger 4' is freely slidable in the axial direction in the center hole of the body 1 '. There is no fitting. Thus, a wedge groove 5 'is provided on the outer periphery of the plunger 4' in three equal parts (only one direction is shown) as shown in FIG. 3, and is provided inside the master jaw 2 '. It engages with the projection 2'a. The details of the meshing state are shown in FIG. 4, which is an enlarged view cut along the line XX 'of FIG. Such a chuck having a structure in which the inner portion of the jaw is provided with a meshing means has the following operational defects. When an operation for grasping the outer diameter of the workpiece (not shown) is performed by the top jaw 3 ', a force indicated by an arrow P is applied to the protrusion 2'a of the master jaw 2' in a radially outward direction. This force P is applied to the jaw 4'b, and the projecting member which forms the inverted T-shaped wedge groove 4'a of the plunger 4 'by the action of the load contacts the hole of the body 1'. The bending moment M acts in the direction of the arrow starting from the portion Q where the two are separated. When the acting force P further increases, the portion is subjected to the concentration of stress due to elastic deformation, and damage such as the zigzag line 6 proceeds. On the other hand, when an operation for grasping the inner diameter of the workpiece (not shown) is performed by the top jaw 3 ', a force in the direction opposite to the arrow P is applied to the protrusion 2'a of the master jaw 2' inward in the radial direction. The bending moment M acts on the overhanging member in the direction opposite to the direction of the arrow by the action of this force. That is, both the force in the direction of arrow P and the force in the direction opposite to arrow P are applied to the jaw 4'b. In other words, there is a disadvantage that the overhanging member that forms the wedge groove 4'a under the load of the force P must always carry the swing load. The force applied to the jaw 4'b is not limited to the structure of the jaw having the meshing means in the inner part in the above example, but also the structure of the jaw having the meshing means in the rear inner part (for example, 55-106707, FIG. 1 and FIG.
No. 9081). In contrast to the above-described conventional chuck structure, this embodiment has a structure in which the outer peripheral surface G of the jaw of the plunger 4 is supported by the inner peripheral surface F of the hole of the body 1 as shown in FIG. By devising the action, the damage caused by the zigzag wire 6 is completely prevented. [Operation] In the present embodiment, the plunger 4 is slid forward and backward in the axial direction of the body by operating a cylinder (not shown) using the chuck having the above-described structure. When the top jaws 3 are simultaneously actuated by the axially acting force of the plunger 4 accompanying the sliding movement and the outer diameter of the workpiece is grasped, the protruding portions 12 of the respective master jaws 2 move radially inward. A load is generated. Thus, the load is applied to the wedge member 50 of the protruding portion 12 by pressing and damaging the component (surface pressure load component), and is applied to the reinforcing member 60 of the protruding portion 12 by bending and breaking the component (bending load component). It is divided and carried. Contrary to this grasp, when grasping the inner diameter of the workpiece, the protrusion 12
The radially outward load is generated, and the load is divided into a surface pressure load component and a bending load component in the opposite directions different from the grasp of the outer diameter. Therefore, the wedge member 50 has a component loading function by a double swing load in which the loading direction differs depending on the grasp of the outer diameter and the grasp of the inner diameter. Next, the mechanical strength of the plunger 4 is examined.
Has a structure in which the reaction force of the above-mentioned surface pressure load component is received by the jaw surface T which forms the surface defining the lateral space 5b of the jaw V in the projecting member which forms the wedge groove 5, so that this surface pressure The shape is such that it can sufficiently withstand the reaction force of the load. However, when the gripping force of the workpiece is further increased to increase the load to be carried, the overhanging member receives a bending moment M in the direction of arrow P as shown in FIG. 4 and is elastically deformed outward in the radial direction. Bending occurs. In such a case, since the outer peripheral surface G of the jaw V is supported by the inner peripheral surface F near the slot groove 11, the bending stress of the jaw V does not increase and is carried as a compressive stress, and the zigzag line 6 in FIG. Such breakage does not progress at all. However, the surface supporting the outer peripheral surface G of the jaw V in this manner is the plunger 4.
It is needless to say that it is desirable to have a structure formed over the entire range of movement of. On the other hand, when the inner diameter of the workpiece is grasped by the top jaw 3, the wedge member 5 of the projection 12 is formed.
At 0, a load is generated outward in the radial direction. Thus, as is clear from the above description, since the surface pressure load component of the plunger 4 to the jaw V is not applied at all, there is no need to share the component force. That is, the overhanging member serves as a component bearing mechanism by a pulsating load that is completely different from the conventional pulsating load. [Other Embodiments] To describe another embodiment, the outer peripheral surface G of the jaw V of the plunger 4 is formed in an arc to the edge of the wedge groove 5 as shown in FIG. It is desirable that the area which is sufficiently large to come into contact with the inner peripheral surface F is large. Even if the opposing outer peripheral front corner end faces of the jaws, which are part of this arc, are cut from the engagement relationship with the master jaw 2, the width of the radial space 5a of the wedge groove as shown in FIG. Is preferably smaller than the width D of the wedge member 50 of the master jaw 2, and if H <D, the same operation and effect as in the example of the arc can be obtained. The wedge groove shape of the plunger is not only a simple inverted T-shape as shown in FIG. 8, but also a slim space N at both lateral ends of the lateral space 5b of the wedge groove as shown in FIG. To prevent local damage due to the force acting on the jaw surface T, which forms the surface defining the lateral space 5b of the jaw V, by dispersing the concentrated stress.
As shown in FIG. 2, the jaw surface T is formed on a roof-shaped inclined surface consisting of a straight line or a curve whose thickness gradually decreases toward the center line of the wedge groove 5, and a bending moment M as a load.
In this case, it is possible to further enhance the strength of safety by forming a rational shape corresponding to the above. [Effect of the Invention] Since the present invention is configured as described above, in the plunger, the overhanging member forming the wedge groove that is mechanically weak is reinforced by utilizing the rigidity of the body. A powerful and unprecedented gripping accuracy can be obtained, and the rigidity of the body will be affected by the ingenuity of forming slot grooves that leave an appropriate amount of thicker portion in the radially outward direction. It will not be done. Furthermore, the chuck structure obtained by constructing these into a combination that is mechanically rational has a balanced mechanical strength compared to conventional chucks, greatly improving rigidity, and having a strong ultra-high strength. The grasping power can be obtained, and the grasping accuracy can be dramatically improved. Furthermore, the structure in which the reinforcing member of the jaw can be accommodated in the slot groove of the body allows the body thickness of the chuck to be extremely thin, and the axial movement amount of the plunger can be increased, so that the jaw movement amount in the radial direction is large. It has a remarkable effect. The improvement of the gripping force obtained by devising the shape of the protruding portion of the jaw is particularly effective in speeding up the cutting speed and preventing a decrease in accuracy accompanying the speed up. Moreover, the reduced weight of the protruding portion of the jaw has a remarkable effect of exhibiting excellent performance in reducing the inertial force in a high rotation range.

【図面の簡単な説明】第１〜第４図は従来の構造を示すもので、第１図はチャックの上部縦断面図、
第２図はマスタ−ジョウの斜視図、第３図はプランジャの部分斜視図、第４図は
第１図のＸ−Ｘ′線切断拡大図、第５図〜第１２図は具体的な実施例を示すもの
で、第５図はチャックの縦断面図、第６図はボディの部分斜視図、第７図はマス
タ−ジョウの斜視図、第８図は第５図のＹ−Ｙ′線切断端面拡大図、第９図及び
第１０図はプランジャの部分斜視図、第１１図及び第１２図はプランジャのウェッジ溝形状の他の例、第１３図は従来構造を示すボディの部分斜視図である。１・・・・・・ボディ２・・・・・・マスタ−ジョウ３・・・・・・トップジョウ４・・・・・・プランジャ５（４′ａ）・・・・・・ウェッジ溝Ｖ（４′ｂ）・・・・・・顎部１２・・・・・・突出部１０・・・・・・案内溝１１・・・・・・スロット溝５０・・・・・・楔部材６０・・・・・・補強部材BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 to FIG. 4 show a conventional structure, FIG.
2 is a perspective view of the master jaw, FIG. 3 is a partial perspective view of the plunger, FIG. 4 is an enlarged view cut along line XX 'of FIG. 1, and FIGS. FIG. 5 is a longitudinal sectional view of the chuck, FIG. 6 is a partial perspective view of the body, FIG. 7 is a perspective view of the master jaw, and FIG. 8 is a line YY 'in FIG. 9 and 10 are partial perspective views of the plunger, FIGS. 11 and 12 are other examples of wedge groove shapes of the plunger, and FIG. 13 is a partial perspective view of a body showing a conventional structure. It is. 1 Body 2 Master jaw 3 Top jaw 4 Plunger 5 (4'a) Wedge groove V (4'b)... Jaw 12... Protruding portion 10... Guide groove 11... Slot groove 50. ... Reinforcing members

Claims

Claims: 1. A body having a body center hole and a plurality of guide grooves in a radial direction.
One plunger having a plurality of wedge grooves corresponding to the guide grooves by slidingly moving the body center hole forward and rearward in the axial direction; and interlocking with the sliding movement of the plunger, radially inward and outward of the body. A chuck composed of a plurality of jaws slidably moving in the direction is configured as follows. (A) The plunger has a pair in which each wedge groove 5 is formed in a space having an inverted T-shaped cross section. (A) each guide groove of the plurality of jaws provided in the body is provided with a slot groove (11) at a groove bottom portion thereof; Of the pair of jaws (V) is formed to be narrower than a portion that is easily damaged when each of the pair of jaws (V) is deformed and damaged by the action of a bending force, and the slot groove (11) has a radius of the body. Appropriate wall thickness (W) (C) a projection (12) is provided behind the jaw, and the projection is a wedge member (
50) and a reinforcing member (60) orthogonal to the wedge member and having a smaller width than the wedge member. (D) Each of the wedge members (50) of each jaw includes a plurality of wedge members provided on the plunger. (E) the reinforcing member (60) is formed in a shape including a portion accommodated in the slot groove (11); F) The outer peripheral surface (G) of the fragile portion is supported by the inner peripheral surface (F) of the body center hole near the slot groove (11) when deformed by the action of bending force. That you are. 2. The inverted T-shaped space of the wedge groove (5) of the plunger extends in the radial direction of the plunger and opens in the outer peripheral surface of the plunger and extends in a direction substantially perpendicular to the radial space. 2. The chuck device according to claim 1, wherein the chucking device comprises a lateral space, and radially outer jaw surfaces defining the lateral space are inclined in a roof shape on both sides of the radial space. 3. An outer peripheral surface (G) of the jaw (V) is supported by an inner peripheral surface (F) in contact therewith when the chuck device is operated, and at this time, a load received by the jaw (V) is compressed. The chuck device according to claim 1 or 2, wherein the chuck device causes stress. 4. The slot width of the slot groove (A) is substantially equal to the width (B) of the radial space (5b) of the plunger wedge groove (5). Or the chuck device according to claim 3. 5. The jaw of the plunger according to claim 3, wherein the cut width H of the opposing outer peripheral front end faces of the jaws and the width (D) of the wedge member of the jaw have a relationship of H <D. Chuck device. 6. The wedge groove according to claim 1, wherein a slim space N for dispersing concentrated stress is formed at both lateral ends of the lateral space of the wedge groove. A chuck device according to any one of the above. 7. The projection according to claim 1, wherein a length (L) of the projection in the longitudinal direction of the jaw is gradually reduced as it goes in the direction of projection of the projection. The chuck device according to any one of the above.