JP5982979B2

JP5982979B2 - Metal pipe expansion device and method

Info

Publication number: JP5982979B2
Application number: JP2012093637A
Authority: JP
Inventors: 井口　貴朗; 貴朗井口; 橋本　裕二; 裕二橋本; 木村　秀途; 秀途木村
Original assignee: JFE Steel Corp
Current assignee: JFE Steel Corp
Priority date: 2011-04-19
Filing date: 2012-04-17
Publication date: 2016-08-31
Anticipated expiration: 2032-04-17
Also published as: JP2012232343A

Description

本発明は、金属管の拡管装置及び拡管方法に関する。本発明は、特に管構造において部分的に管径の異なる部品を製造するのに好適であり、管端拡管に限らず、全長拡管にも適用される。 The present invention relates to a pipe expanding device and a pipe expanding method for a metal pipe. The present invention is particularly suitable for manufacturing parts having partially different pipe diameters in a pipe structure, and is applicable not only to pipe end pipe expansion but also to full length pipe expansion.

例えば図６に示す様な自動車用のステアリングハンガービームを製造するには、直径の異なる全２種類の金属管を用意し、一方の管端側をテーパ状に成形した上で溶接接合するのが一般的である。また、図７に示す様なサスペンションメンバ部品は、閉断面構造であるが、金属板を成形して上下モナカ構造とし、端面を溶接して製造するのが一般的である。もしこれらの部品を一本のパイプの片端を拡管若しくは縮管して製造できれば、製造コストの低減及び溶接不要による信頼性の向上が期待できる。 For example, in order to manufacture a steering hanger beam for an automobile as shown in FIG. 6, two types of metal tubes having different diameters are prepared, and one of the tube ends is formed into a tapered shape and welded. It is common. The suspension member component as shown in FIG. 7 has a closed cross-sectional structure, but is generally manufactured by molding a metal plate to form an upper and lower monaca structure and welding end faces. If these parts can be manufactured by expanding or contracting one end of a single pipe, it is possible to expect a reduction in manufacturing cost and an improvement in reliability due to the absence of welding.

然しながら、大径側と小径側の径差が大きいと、そのような加工は困難である。例えば、従来の管端拡管技術は、管への圧入先端側を小径端としたテーパ部の大径端側に平行部が連なる形状を有する１つのパンチと、パンチ形状に対応したテーパ形状を有する１つの金型とを用い、管を金型内に配置して固定し、管端からパンチを圧入して、１段階で拡管するものであった（特許文献１参照）。しかし、１回あたりの拡管量には限界がある。それは押し荷重増大による素管の座屈、管端部のひずみ蓄積による割れのためである。 However, if the diameter difference between the large diameter side and the small diameter side is large, such processing is difficult. For example, the conventional tube end pipe expanding technique has one punch having a shape in which a parallel portion is connected to a large diameter end side of a tapered portion having a small diameter end at a press-fitting tip side into the tube, and a taper shape corresponding to the punch shape. Using one mold, the pipe was placed and fixed in the mold, a punch was press-fitted from the end of the pipe, and the pipe was expanded in one stage (see Patent Document 1). However, there is a limit to the amount of pipe expansion per time. This is due to the buckling of the raw pipe due to an increase in the pushing load and the cracking due to the accumulation of strain at the end of the pipe.

そこで、多段拡管技術が提案された（特許文献２、３参照）。これは、例えば図５に示すように、テーパ部のテーパ角θが同じで径が異なる２つ以上のパンチ12A,12B,12Cと、パンチ形状に対応したテーパ型形状を有する１つのダイである金型13とを用い、管11を金型13内に配置して固定し、管端からパンチを圧入して拡管するにあたり、パンチを径の小さいものから順に入れ替えて圧入し、多段階的に拡管するものである。これによると、１回の拡管における管とパンチとの接触面積を小さくとれるので、拡管における座屈の危険を回避しつつ、又、１段階当たりのひずみ量を小さくして、端部割れを回避しつつ、繰り返し拡管によって、全拡管量を大きくとることができる。 Therefore, a multistage tube expansion technique has been proposed (see Patent Documents 2 and 3). This is, for example, as shown in FIG. 5, two or more punches 12A, 12B, 12C having the same taper angle θ and different diameters, and one die having a taper shape corresponding to the punch shape. Using the mold 13, the pipe 11 is placed and fixed in the mold 13, and when the punch is press-fitted from the pipe end to expand the pipe, the punch is changed in order from the smallest diameter, and press-fitted in multiple steps. It is to be expanded. According to this, since the contact area between the tube and the punch in one expansion can be reduced, the risk of buckling in the expansion is avoided, and the strain per step is reduced to avoid end cracks. However, the total amount of pipe expansion can be increased by repeated pipe expansion.

特開２００９−５０８８８号公報JP 2009-50888 A 特開平１１−２３９８３５号公報JP-A-11-239835 特開２００２−３４６６６４号公報JP 2002-346664 A

しかしながら、上記従来の多段階拡管においては、同一管に対して異なるパンチを入れ替えて圧入することによる、工程数、工程時間の増加や、加工装置の複雑化による生産コストの上昇が問題である。又、２回目（第２段階又は第２工程ともいう）以降の拡管においては素管の固定が不十分なために、図４に示すように座屈が発生しやすく、拡管量が大きくとれない。 However, in the conventional multi-stage pipe expansion, there are problems in that the number of processes and the process time are increased and the production cost is increased due to the complexity of the processing apparatus by replacing and inserting different punches into the same pipe. In addition, in the second and subsequent expansions (also referred to as the second stage or the second step), since the raw tube is not sufficiently fixed, buckling is likely to occur as shown in FIG. 4, and the amount of expansion is not large. .

発明者らは、上記課題を解決するために、多段階拡管においてパンチの入れ替え無く連続して圧入でき、且つ、２回目以降の拡管においても素管を確実に固定できる手段を検討し、本発明をなした。即ち本発明は以下のとおりである。なお、特許請求の範囲に記載の発明は、以下の本発明(1)〜(4)のうちの少なくともいずれか１つである。
(1)
管への圧入先端側を小径端としたテーパ部の大径端側に平行部が連なる形状を有する１つのパンチと、パンチ形状に対応したテーパ形状を有する1つの金型とを備えた金属管の拡管装置において、前記パンチは、半径方向に同心円状の多層構造をなし、該多層構造の各層である段パンチが圧入により軸方向に摺動する構成とされてなることを特徴とする金属管の拡管装置。
(2)
前記パンチは、前記各層の段パンチに加え、パンチ中心軸と同軸上に圧入軸を備え、該圧入軸には、前記段パンチを内層側から順次押す階段形状のキーが軸周上に１つ又は複数固定され、前記段パンチのうち少なくとも最外層以外の段パンチの平行部には前記キーをかわすための溝が部分的に段パンチ最後部より形成され、以て前記圧入軸の回転角度調整によって前記段パンチを選択して圧入する構成とされてなることを特徴とする上記(1)に記載の金属管の拡管装置。
(3)
前記パンチは、外層がその摺動し合う内層に対して後方に抜けるのを防止するストッパ構造を有することを特徴とする上記(1)又は(2)に記載の金属管の拡管装置。
(4)
上記(1)〜(3)の何れかに記載の装置を用いる金属管の拡管方法であって、管を前記金型に配置して固定し、管端から前記パンチを圧入するにあたり、径の小さい段パンチから順に圧入し、先行段パンチの圧入完了状態を保持したまま後続段パンチの圧入を行うことを特徴とする金属管の拡管方法。 In order to solve the above-mentioned problems, the inventors have studied a means capable of continuously press-fitting without replacing the punches in multi-stage pipe expansion, and capable of reliably fixing the element pipe in the second and subsequent pipe expansions. Made. That is, the present invention is as follows. The invention described in the claims is at least one of the following present inventions (1) to (4).
(1)
A metal tube comprising one punch having a shape in which a parallel portion is connected to the large diameter end side of the tapered portion with a small diameter end at the press-fitting tip side into the tube, and one die having a tapered shape corresponding to the punch shape In this pipe expanding device, the punch has a multi-layer structure that is concentric in the radial direction, and the step punch that is each layer of the multi-layer structure is configured to slide in the axial direction by press-fitting. Tube expansion equipment.
(2)
The punch has a press-fit shaft coaxially with the punch center axis in addition to the step punch of each layer, and the press-fit shaft has one step-shaped key on the axis circumference that sequentially presses the step punch from the inner layer side. Or, a plurality of fixed punches, and a groove for dodging the key is partially formed in the parallel portion of the step punch other than the outermost layer among the step punches, so that the rotation angle of the press-fit shaft is adjusted. The metal pipe expanding apparatus according to (1) above, wherein the step punch is selected and press-fitted.
(3)
2. The metal tube expansion device according to (1) or (2), wherein the punch has a stopper structure that prevents the outer layer from slipping backward with respect to the sliding inner layer.
(Four)
A method of expanding a metal pipe using the apparatus according to any one of (1) to (3) above, wherein the pipe is arranged and fixed in the mold, and the diameter of the punch is press-fitted from the pipe end. A method of expanding a metal tube, wherein press fitting is performed in order from a small step punch, and the subsequent step punch is press-fitted while maintaining the press-fitting completion state of the preceding step punch.

本発明によれば、拡管加工を高速且つ高能率に行うことができる。又、TS（引張強さ）５９０MPa級の高強度鋼管でも拡管率１００％以上の拡管が可能である。 According to the present invention, tube expansion processing can be performed at high speed and high efficiency. Moreover, even with a TS (tensile strength) 590 MPa class high-strength steel pipe, it is possible to expand the pipe with a pipe expansion rate of 100% or more.

本発明の実施形態の例（１）を示す断面図である。It is sectional drawing which shows the example (1) of embodiment of this invention. 本発明の実施形態の例（２）を示す断面図である。It is sectional drawing which shows the example (2) of embodiment of this invention. 実施例の目標拡管形状を示す側面図である。It is a side view which shows the target pipe expansion shape of an Example. 従来技術の問題点を示す断面図である。It is sectional drawing which shows the problem of a prior art. 従来技術の１例を示す断面図である。It is sectional drawing which shows one example of a prior art. ステアリングハンガービームの形状例を示す外観図である。It is an external view which shows the example of a shape of a steering hanger beam. サスペンションメンバ部品の形状例を示す外観図である。It is an external view which shows the example of a shape of suspension member components. 本発明を好適に実施するパンチ構造を示す外観図である。It is an external view which shows the punch structure which implements this invention suitably. 本発明を好適に実施する軸押し部品形状例を示す外観図である。It is an external view which shows the example of a shaft pushing component shape which implements this invention suitably. 本発明を好適に実施するパンチの部品形状例（a）及び本発明をさらに好適に実施するパンチの部品形状例（b）を示す外観図である。It is an external view which shows the component shape example (a) of the punch which implements this invention suitably, and the component shape example (b) of the punch which implements this invention more suitably.

図１、図２は本発明の実施形態の例（１）、例(２)を示す断面図である。本発明に係る拡管装置において、金型13は従来のものと同様であるが、パンチ1は従来にないものである。即ち、本発明のパンチ1は図１に例示されるとおり、管11への圧入先端側を小径端としたテーパ部の大径端側に平行部が連なる形状を有するという前提においては従来と同様であるが、半径方向に同心円状の多層構造をなし、該多層構造の各層1a,1b,1c,1dである段パンチ1a,1b,1c,1dがそれぞれ個別に圧入により軸方向に摺動する構成とされてなるという点で従来にないものである。尚、例（１）〜（２）では４層としたが、２層、３層、５層以上であってもよい。 1 and 2 are cross-sectional views showing examples (1) and (2) of an embodiment of the present invention. In the tube expanding apparatus according to the present invention, the mold 13 is the same as the conventional one, but the punch 1 is not the conventional one. That is, as illustrated in FIG. 1, the punch 1 of the present invention is similar to the conventional one on the premise that the parallel portion is connected to the large diameter end side of the taper portion where the tip end side of the tube 11 is the small diameter end. However, a multi-layer structure concentric in the radial direction is formed, and the step punches 1a, 1b, 1c, 1d, which are the layers 1a, 1b, 1c, 1d of the multi-layer structure, individually slide in the axial direction by press-fitting. It is not in the past in that it is configured. In Examples (1) to (2), four layers are used, but two layers, three layers, five layers or more may be used.

パンチ1を用いることで、管11を金型13に配置して固定し、管端からパンチ1を圧入するにあたり、径の小さい段パンチから順に、例えば第１〜第４工程で層（段パンチ）1a,1b,1c,1dの順に圧入し、先行段パンチの圧入完了状態を保持したまま後続段パンチの圧入を行うことができる。この拡管方法により、パンチを入れ替えることなく連続して拡管することができるから、高速且つ高能率に拡管することができる。しかも、管の既拡管テーパ部が先行段パンチのテーパ部にて金型13のテーパ部に押圧固定されるから、第２工程以降の素管に対して図４のような座屈を防止できて、拡管率を大きくとることができる。 By using the punch 1, the tube 11 is arranged and fixed on the mold 13, and when the punch 1 is press-fitted from the end of the tube, the layers (step punches, for example, in the first to fourth steps in order from the step punch with the smallest diameter). ) 1a, 1b, 1c, and 1d are press-fitted in order, and the subsequent-stage punch can be press-fitted while maintaining the press-fitting completion state of the preceding-stage punch. By this tube expansion method, the tube can be continuously expanded without replacing the punch, so that the tube can be expanded at high speed and with high efficiency. Moreover, since the already expanded taper portion of the pipe is pressed and fixed to the taper portion of the mold 13 by the taper portion of the preceding stage punch, it is possible to prevent buckling as shown in FIG. Therefore, the tube expansion rate can be increased.

尚、図１（例（１））、図２(例（２）)において層の押し手段は図示していないが、例（１）ではテーパ部が階段状をなす初期状態から拡管を開始し、例(２)ではテーパ部が面一をなす初期状態から拡管を開始するが、何れも、順次、先行層の圧入完了後直ちに後続層の圧入が開始できるようにしている。
上記のような、段パンチ1a,1b,1c,1dの前記動作を可能にする機構については、当該動作が可能であれば特に限定されるものではないが、実際はかなり複雑な機構を要する。発明者らは斯かる動作を好適に推進させうるパンチ駆動機構をも発明したので、以下に其の例を示す。 In FIG. 1 (example (1)) and FIG. 2 (example (2)), the pushing means of the layer is not shown, but in example (1), tube expansion starts from the initial state where the tapered portion forms a step shape. In the example (2), the tube expansion is started from the initial state in which the tapered portion is flush with each other. In any case, the press-fitting of the succeeding layer can be started immediately after the press-fitting of the preceding layer is sequentially completed.
The mechanism that enables the operation of the step punches 1a, 1b, 1c, and 1d as described above is not particularly limited as long as the operation is possible, but actually requires a considerably complicated mechanism. The inventors have also invented a punch drive mechanism that can suitably promote such operation, and an example thereof will be shown below.

図８は本発明を好適に実施するパンチ構造を示す外観図である。31は層押し手段として、パンチ中心軸と同軸上に備えられ、パンチ全体を圧入する為の圧入軸である。さて、圧入軸31には、段パンチ1a,1b,1cを、これらの端面を押して圧入することができるよう、キー31aが固定されている。また、31bは別の支持台であって、段パンチ1dの端面に接触、接合する構造とされる。キー31aと支持台31bは階段状に形成されており、各段パンチの後端が接触した状態では図８(a)に示す様に各段パンチの同心軸方向位置は圧入前のステップ状にシフトされた状態になる。斯かる圧入軸31、キー31a、支持台31bからなる軸押し部品の外観は例えば図９のようになる。この例では円周方向に３組のキー31aが配されているが、これは押し力の均一化の為であって個数を限定するものではない。 FIG. 8 is an external view showing a punch structure for favorably implementing the present invention. Reference numeral 31 denotes a press-fitting shaft provided as a layer pressing means coaxially with the punch central axis, for press-fitting the entire punch. A key 31a is fixed to the press-fit shaft 31 so that the step punches 1a, 1b, and 1c can be press-fitted by pressing their end faces. Reference numeral 31b denotes another support, which is configured to contact and join the end face of the step punch 1d. The key 31a and the support base 31b are formed in a step shape, and when the rear end of each step punch is in contact, the concentric axial position of each step punch is in a step shape before press-fitting as shown in FIG. 8 (a). It becomes a shifted state. The appearance of such a press-fitting component comprising the press-fit shaft 31, the key 31a, and the support base 31b is as shown in FIG. 9, for example. In this example, three sets of keys 31a are arranged in the circumferential direction, but this is for the purpose of equalizing the pressing force and does not limit the number.

圧入軸31と段パンチ1aは回転自在・軸方向摺動自在に組み合わさっているが、段パンチ1aと1b、及び段パンチ1bと1cは夫々図示しない埋め込みキーによって相対回転をしないように、然し軸方向には摺動するように、構成されている。尚、段パンチ1dについては、段パンチ１ｃと同様に埋め込みキーで相互回転不可に固定する構造と、段パンチ１ｃとは相対回転自在で支持台31bに固定する構造のどちらでも良い。 The press-fit shaft 31 and the step punch 1a are combined so as to be rotatable and slidable in the axial direction. However, the step punches 1a and 1b and the step punches 1b and 1c are not rotated relative to each other by an embedded key (not shown). It is configured to slide in the axial direction. Incidentally, the step punch 1d may be either a structure that is fixed so as not to be mutually rotatable with an embedding key like the step punch 1c, or a structure that is relatively rotatable with respect to the step punch 1c and fixed to the support base 31b.

各層の段パンチ1a,1b,1cは立体視すると例えば図１０(a)の様になっており、平行部の一部には後端から溝が形成されている。これはキー31aが特定の位置に来たとき、それをかわして押込み力を伝達させない配設形態とされている。ただし、段パンチ1aは圧入軸31とは別の中心軸32にキー固定し、段パンチ全体が回転しないようにしておくことが望ましい。 The step punches 1a, 1b, and 1c of each layer are, for example, as shown in FIG. 10A when viewed three-dimensionally, and a groove is formed in a part of the parallel portion from the rear end. This is an arrangement in which when the key 31a comes to a specific position, it does not transmit the pushing force by avoiding it. However, it is desirable that the step punch 1a is keyed to a central shaft 32 different from the press-fit shaft 31 so that the entire step punch does not rotate.

パンチ全体を組み上げた構成は図８(a)〜(d)に示した様になる。図８(a)では横断面図に示す様に断面A-Aにおいてキー31aは段パンチ1a,1b,1cの何れの端面とも接触しており、又段パンチ1dは支持台31bと常時接しているので、圧入軸31の押し込み（図の左方向へ）によって全ての段パンチが図の左方向へと移動する。よって先ず、段パンチ1aによって第1段階（第1工程）の拡管が行われる。 The structure in which the entire punch is assembled is as shown in FIGS. In FIG. 8A, the key 31a is in contact with any end face of the step punches 1a, 1b, 1c and the step punch 1d is always in contact with the support base 31b in the section AA as shown in the cross-sectional view. By pushing the press-fit shaft 31 (to the left in the figure), all the step punches move to the left in the figure. Therefore, first, the first stage (first process) is expanded by the step punch 1a.

第1段階の押し込みが終了すると、段パンチ1aは管11を介して金型13に接するため、それ以上前進できなくなる。この時点で圧入軸31を３０°回転させると図８(b)の如くとなり、キー31aは断面B-Bにおいて段パンチ1aの端面から外れ、段パンチ1b、1cのみを押す様相となる、ここでさらに圧入軸31が前進すると段パンチ1aは静止したまま、段パンチ1b,1c,1dが圧入されて第２段階（第２工程）の拡管が実行される。 When the first step of pushing is completed, the step punch 1a comes into contact with the mold 13 through the tube 11, and cannot move forward any further. At this point, when the press-fit shaft 31 is rotated by 30 °, the result is as shown in FIG. 8B, and the key 31a is disengaged from the end face of the step punch 1a in the cross section BB, and only the step punches 1b and 1c are pressed. When the press-fit shaft 31 moves forward, the step punch 1a remains stationary and the step punches 1b, 1c, 1d are press-fitted and the second stage (second step) of pipe expansion is executed.

さらに圧入軸31を３０°回転させると図８(c)の様になり、第３段階（第３工程）の拡管が実行される。さらに圧入軸31を３０°回転させると図８(d)の様になり、第４段階（第４工程）の拡管が実行される。
以上の様な構造を採れば本発明に係る多段拡管を好適に実施できるのであるが、更なる改良形を以下に示す。 Further, when the press-fit shaft 31 is rotated by 30 °, as shown in FIG. 8C, the third stage (third process) of the pipe expansion is executed. When the press-fit shaft 31 is further rotated by 30 °, the result is as shown in FIG. 8D, and the fourth stage (fourth process) of pipe expansion is executed.
The multi-stage expansion according to the present invention can be suitably carried out by adopting the structure as described above, and further improvements will be described below.

例えば第１段階の拡管が終了した後、圧入軸31を回転させて第２段階の圧入を開始すると、段パンチ1aは軸方向に拘束が無くなり軸方向移動が可能となる。段パンチ1aは実際には圧入軸31と段パンチ1bとの相対摩擦により、引き続き進行方向に軸力を受けて金型13側に押し付けられるのであるが、材料を拘束する力は弱くなる。そこで、段パンチ1aの溝を例えば図１０(b)の様に段付きにし、段の長さを次層以降の段パンチのストロークを考慮して決定しておけば、第２段階の拡管で段パンチ1bが金型13に押し付けられるタイミングにおいて同時に段パンチ1aも金型13に押し付けられる様、軸力を受けることができるので、管11材料の座屈を効果的に抑えることができ、良好である。 For example, after the first-stage expansion is completed, when the second-stage press-fitting is started by rotating the press-fitting shaft 31, the step punch 1a is not restricted in the axial direction and can be moved in the axial direction. The step punch 1a is actually pressed against the mold 13 by receiving the axial force in the advancing direction due to the relative friction between the press-fit shaft 31 and the step punch 1b, but the force for restraining the material becomes weak. Therefore, if the groove of the step punch 1a is stepped as shown in FIG. 10 (b), for example, the length of the step is determined in consideration of the stroke of the step punch after the next layer. As the step punch 1a is pressed against the mold 13 at the same time as the step punch 1b is pressed against the mold 13, it can receive an axial force, effectively suppressing the buckling of the tube 11 material, and good It is.

又、別の改良として、段パンチ1a,1b,1c,1dには、夫々その外側の段パンチが相対的に後退方向に抜けないようにするストッパ35を設けておく事が考えられる。これによる作用効果は以下の通りである。即ち、図８(d)の状態で、拡管加工が終了した後、パンチ全体を引抜く必要がある。そこで図８(d)の状態から圧入軸31を引き抜くと、先ず段パンチ1dが後退するが、その他の段パンチには軸力が作用しないので、図８(c)の状態になる。その時点でストッパ35の作用により段パンチ1cの引き抜きが開始されて図８(b)の状態となり、更に図８(a)の状態となって、自動的に元の状態に復帰する。ここから圧入軸31を３０°回転させれば、再び次材の拡管工程にそのまま移行する事が可能である。その引き抜きの際、図示しない固定装置で段パンチ1aの移動を拘束できればなお好適である。 As another improvement, it is conceivable that the step punches 1a, 1b, 1c, 1d are each provided with a stopper 35 that prevents the outer step punches from coming out in the backward direction. The effect by this is as follows. That is, in the state of FIG. 8D, after the tube expansion process is completed, it is necessary to pull out the entire punch. Therefore, when the press-fit shaft 31 is pulled out from the state shown in FIG. 8 (d), the step punch 1d first retracts, but no axial force acts on the other step punches, so the state shown in FIG. 8 (c) is obtained. At that time, the pulling of the step punch 1c is started by the action of the stopper 35, and the state shown in FIG. 8B is obtained. Further, the state shown in FIG. 8A is automatically restored to the original state. If the press-fit shaft 31 is rotated by 30 ° from here, it is possible to move again to the tube expansion process of the next material. It is even more preferable if the movement of the step punch 1a can be restrained by a fixing device (not shown) at the time of drawing.

素管には、外径５１ｍｍ、肉厚２．３ｍｍの電縫溶接鋼管を長さ５００ｍｍに切断して用いた。素管材質はTS５９０MPa級炭素鋼である。この素管に種々の条件で多段階拡管による管端拡管加工を施す実験を行った。最終拡管形状（目標拡管形状）は、図３に示すとおり、拡管平行部22の長さ＝１００ｍｍ、外径＝１１０ｍｍとし、拡管テーパ角θを２０〜４０度の範囲で変化させた。加工条件は、段階数（工程数）を３〜５の範囲で変化させ、又、一部には中間工程出側外径（最終工程前の各工程出側の管外径）を変化させた。用いた管端拡管装置のパンチテーパ角及び金型テーパ角は拡管テーパ角θと同じ角度とした。 As the base pipe, an electric resistance welded steel pipe having an outer diameter of 51 mm and a wall thickness of 2.3 mm was cut into a length of 500 mm. The raw tube material is TS590 MPa class carbon steel. Experiments were conducted on the pipes to perform pipe end expansion by multistage expansion under various conditions. As shown in FIG. 3, the final tube expansion shape (target tube expansion shape) was such that the length of the tube expansion parallel portion 22 was 100 mm and the outer diameter was 110 mm, and the tube expansion taper angle θ was changed in the range of 20 to 40 degrees. The processing conditions were changed in the number of steps (number of steps) in the range of 3-5, and in some cases, the outer diameter of the intermediate process outlet (the outer diameter of the pipe on the outlet side of each process before the final process) was changed. . The punch taper angle and die taper angle of the pipe end pipe expanding device used were the same as the pipe expansion taper angle θ.

本発明例では、図１に示したパンチ1において層数を工程数と同数とし、同図に示したのと同様の圧入形態で拡管した（同軸式と仮称）。パンチの各層の平行部径は、対応する工程出側の管内径（＝外径-肉厚＊２）に合わせた。従来例では、図５のように径の異なるパンチ12を入れ替えて使用する圧入形態（入替式と仮称）とし、各工程のパンチ平行部径は対応する工程出側の管内径に合わせた。尚、被加工面には水系揮発型潤滑油を適用した。 In the example of the present invention, the number of layers in the punch 1 shown in FIG. 1 was the same as the number of steps, and the tube was expanded in the same press-fitting form as shown in the figure (coaxial type and tentative name). The parallel part diameter of each layer of the punch was adjusted to the corresponding pipe inner diameter (= outer diameter−thickness * 2) on the process exit side. In the conventional example, as shown in FIG. 5, a press-fitting form (changeable type and tentative name) is used in which the punches 12 having different diameters are replaced, and the diameter of the punch parallel portion in each process is matched with the corresponding pipe inner diameter on the process exit side. A water-based volatile lubricant was applied to the work surface.

加工条件及び加工後形状判定結果を、工程数別、或いは中間工程出側外径別に分けて、表１〜４に示す。表１〜４において「○」は加工後形状が良好であったことを意味する。「―」は前工程で形状不良が起きて、それ以降には進めなかったことを意味する。
結果をみると、３段階拡管では、表１に示されるとおり、本発明例、従来例とも形状不良を生じたが、従来例が第２工程で座屈を生じて最終工程まで進めなかったのに対し、本発明例では最終工程まで進むことができた。但しそこで端面割れを生じた。 The processing conditions and post-processing shape determination results are shown in Tables 1 to 4 for each number of processes or for each intermediate process outlet outer diameter. In Tables 1 to 4, “◯” means that the shape after processing was good. “-” Means that a shape defect occurred in the previous process and it was not possible to proceed after that.
In the three-stage tube expansion, as shown in Table 1, the example of the present invention and the conventional example produced defective shapes, but the conventional example was buckled in the second step and could not proceed to the final step. On the other hand, in the example of the present invention, it was possible to proceed to the final process. However, end face cracks occurred there.

一方、４段階以上の拡管においては、表２〜４に示されるとおり、従来例が何れも中間工程或いは最終工程で形状不良を起こしたのに対し、本発明例は全て最終工程まで進むことができて良好な最終形状が得られた。このように、本発明によれば、TS５９０MPa級の高強度鋼管を全拡管率１００％まで管端拡管できる。
又、最終工程まで進みえた唯一の従来例である試験No.31（但し最終形状は不良）と、これと同じ工程数の本発明例の中の１つである試験No.36とで、工程全体の加工所要時間を比較したところ、本発明例は従来例の約１/４以下であったことから、本発明により加工能率が格段に向上することが分った。 On the other hand, as shown in Tables 2 to 4, in the expansion of four or more stages, all of the examples of the present invention proceed to the final process, whereas the conventional examples caused a shape defect in the intermediate process or the final process. And a good final shape was obtained. As described above, according to the present invention, a TS590 MPa class high-strength steel pipe can be expanded to a pipe end up to a total expansion ratio of 100%.
In addition, test No. 31 which is the only conventional example that has progressed to the final process (however, the final shape is defective) and test No. 36 that is one of the present invention examples having the same number of processes, When the total processing time was compared, the example of the present invention was about 1/4 or less that of the conventional example, and it was found that the processing efficiency was greatly improved by the present invention.

以上述べたように、本発明によれば、金属管の拡管量をより拡大でき、さらに拡管工程を高速に、能率よく遂行できるから、今まで溶接などで組み立てていた部品を一体で成形したりできるため、コストの削減、性能や信頼性の向上をはかることができる。 As described above, according to the present invention, the amount of expansion of the metal tube can be further increased, and further, the tube expansion process can be performed efficiently at high speed. Therefore, it is possible to reduce costs and improve performance and reliability.

1 パンチ（本発明）
1a,1b,1c,1d 層(段パンチ)
11 管
12 パンチ（従来）
13 金型
21 拡管テーパ部
22 拡管平行部
31 層押し手段（圧入軸）
31a キー
31b 支持台
32 中心軸
35 ストッパ 1 Punch (Invention)
1a, 1b, 1c, 1d layer (step punch)
11 tubes
12 punch (conventional)
13 Mold
21 Expanded taper section
22 Expanded parallel section
31 Layer pushing means (press-fit shaft)
31a key
31b Support stand
32 Center axis
35 Stopper

Claims

管への圧入先端側を小径端としたテーパ部の大径端側に平行部が連なる形状を有する１つのパンチと、パンチ形状に対応したテーパ形状を有する1つの金型とを備えた金属管の拡管装置において、前記パンチは、半径方向に同心円状の多層構造をなし、該多層構造の各層である段パンチが圧入により軸方向に摺動する構成とされてなること、および、
前記パンチは、前記各層の段パンチに加え、パンチ中心軸と同軸上に圧入軸を備え、該圧入軸には、前記段パンチを内層側から順次押す階段形状のキーが軸周上に１つ又は複数固定され、前記段パンチのうち少なくとも最外層以外の段パンチの平行部には前記キーをかわすための溝が部分的に段パンチ最後部より形成され、以て前記圧入軸の回転角度調整によって前記段パンチを選択して圧入する構成とされてなることを特徴とする金属管の拡管装置。 A metal tube comprising one punch having a shape in which a parallel portion is connected to the large diameter end side of the tapered portion with a small diameter end at the press-fitting tip side into the tube, and one die having a tapered shape corresponding to the punch shape In the pipe expanding device, the punch has a multilayer structure that is concentric in the radial direction, and the step punch that is each layer of the multilayer structure is configured to slide in the axial direction by press-fitting , and
The punch has a press-fit shaft coaxially with the punch center axis in addition to the step punch of each layer, and the press-fit shaft has one step-shaped key on the axis circumference that sequentially presses the step punch from the inner layer side. Or, a plurality of fixed punches, and a groove for dodging the key is partially formed in the parallel portion of the step punch other than the outermost layer among the step punches, so that the rotation angle of the press-fit shaft is adjusted. The metal pipe expansion device is characterized in that the step punch is selected and press-fitted by the above .

管への圧入先端側を小径端としたテーパ部の大径端側に平行部が連なる形状を有する１つのパンチと、パンチ形状に対応したテーパ形状を有する1つの金型とを備えた金属管の拡管装置において、前記パンチは、半径方向に同心円状の多層構造をなし、該多層構造の各層である段パンチが圧入により軸方向に摺動する構成とされてなること、および、
前記パンチは、外層がその摺動し合う内層に対して後方に抜けるのを防止するストッパ構造を有することを特徴とする金属管の拡管装置。 A metal tube comprising one punch having a shape in which a parallel portion is connected to the large diameter end side of the tapered portion with a small diameter end at the press-fitting tip side into the tube, and one die having a tapered shape corresponding to the punch shape In the pipe expanding device, the punch has a multilayer structure that is concentric in the radial direction, and the step punch that is each layer of the multilayer structure is configured to slide in the axial direction by press-fitting, and
The punch is expanding apparatus features and to Rukin genus tube that has a stopper structure for preventing the coming off rearwardly relative to the inner layer outer layer mutually its sliding.

前記パンチは、外層がその摺動し合う内層に対して後方に抜けるのを防止するストッパ構造を有することを特徴とする請求項１に記載の金属管の拡管装置。 The metal pipe expansion device according to claim 1, wherein the punch has a stopper structure that prevents the outer layer from slipping backward with respect to the sliding inner layer.

請求項１〜３の何れかに記載の装置を用いる金属管の拡管方法であって、管を前記金型に配置して固定し、管端から前記パンチを圧入するにあたり、径の小さい段パンチから順に圧入し、先行段パンチの圧入完了状態を保持したまま後続段パンチの圧入を行うことを特徴とする金属管の拡管方法。
A method of expanding a metal pipe using the apparatus according to any one of claims 1 to 3, wherein a pipe is placed in the mold and fixed, and a punch having a small diameter is used to press-fit the punch from the pipe end. A metal tube expanding method, wherein the press-fitting of the succeeding stage punch is performed while maintaining the press-fitting completion state of the preceding stage punch.