【０００１】
【発明の属する技術分野】
この出願は、逐次成形に用いる板材の成形方法に関する。逐次成形とは棒状又は凸型もしくは凹型形状をなす押圧部材を、金属製薄板等へ押し当てながら板材と押圧部材を相対的に移動させることにより、シェル形状等の所定立体形状を成形する公知方法をいう。なお、本願発明においては、成形前の板材平面内における直交２軸方向をＸＹ、これらとそれぞれ直交する軸方向をＺとする。
【０００２】
【従来の技術】
このような逐次成形及び装置はＷＯ９９／３８６２７号等により公知であり、例えば、特開平５−４２３２８号には板材の四辺をしわ押さえにより水平に保持し、下方から凸型状をなす型状押圧部材を押し上げて大まかな形状に予備絞り成形し、上方から棒状押圧部材を押し当てながら板材をＸＹ方向へ移動させ、かつ押圧部材をＺ方向へ移動することにより所望の立体形状を成形するようになっている。特願２００２−０４０４９６号の逐次成形方法によれば雄型又は雌型のいずれか一方又は双方を省略できる利点がある。
【０００３】
また、雄型又は雌型のいずれか一方を省略できる他の成形方法として液圧成形がある。液圧成形は雄型又は雌型のいずれか一方を用い、その成形面へ被加工板材を液圧にて押しつけて所定形状に成形する方法であり、ブロー成形、バルジ成形及び対向液圧成形を含む成形方法である。
【０００４】
さらに、テンション成形と逐次成形方法を組み合わせても雌型を省略できる。すなわちブランクホルダーに把持された被加工板材へ雄型を押しつけることにより短時間で大まか形状に成形し、その後逐次成形方法により細部を成形して成形する方法である（特願２００２−０４３０４９号参照）。
【０００５】
【発明が解決しようとする課題】
逐次成形単独で成形する場合は、成形時間がかかるとともに、表面の広範囲に棒状押圧部材による線条の成形痕が残る。液圧成形のみで細かい形状を正確に成形するには液体の成形圧を極めて高圧にしなければならず、設備が複雑大型化して高価になる。またテンション成形と逐次成形方法を組み合わせる場合は、テンション成形用の高強度な雄型を作らなければならないので、金型コストが高くなる。そこで、本願は逐次成形の利点を維持しつつ、成形時間を短縮し、かつ金型コスト及び設備を低廉にできる成形方法の実現を目的とする。
【０００６】
【課題を解決するための手段】
上記課題を解決するため請求項１に係る板材の成形方法は、被加工板材に棒状押圧部材を押し当てて塑性変形させることにより所定の立体形状を成形する逐次成形方法を用いた板材の成形方法において、前記被加工板材を液圧成形にて大まか形状に成形し、その後逐次成形により細部を成形することを特徴とする。
【０００７】
請求項２は上記請求項１において、前記液圧成形に際して前記大まか形状に相当する成形面を備えた雄型又は雌型のいずれか一方を用いることを特徴とする。
【０００８】
請求項３は上記請求項１又は２において、前記液圧成形は低圧ブロー成形であることを特徴とする。
【０００９】
【発明の効果】
請求項１の発明によれば、逐次成形に先立って、被加工板材を液圧成形にて大まか形状に成形し、その後逐次成形により細部を成形するので、逐次成形を必要最小限にできることになり、成形時間の短縮並びに成形痕を少なくすることができる。しかも液圧成形は細部まで成形する必要がないので、それ程高圧にする必要が無くなるので、設備を簡単小型化でき、設備費用を低減できる。
【００１０】
請求項２の発明によれば、液圧成形に使用する金型として大まか形状に相当する成形面を備えた雄型又は雌型のいずれか一方を用意すれば足り、しかもその金型は比較的低圧用で足り、かつ成形面を大まか形状にしておくこともできるから金型コストを低減できる。
【００１１】
請求項３の発明によれば、液圧成形を低圧ブロー成形としたので、被加工板材の成形を容易かつ低コストで行うことができる。
【００１２】
【発明の実施の形態】
以下、図面に基づいて一実施例を説明する。図１は本実施例に係る成形方法を示す概念図である。図１のＡは液圧成形工程であり、被加工板材１を雄型２上に置いて、その周囲をクランプ３で固定し、液室４へ圧力液体を注入して被加工板材１を成形面５へ押しつけて仮想線のように大まか形状に一次成形する。この成形は低圧ブロー成形である。
【００１３】
被加工板材１は、塑性加工可能な鉄などの金属等からなる適宜材料製の板状材料であり、その板厚も適宜可能である。
雄型２は、低圧ブロー成形に必要な強度を有するものであれば、公知の種々な材料を使用できる。また成形面５が大まか形状で足りるため、全体として低コストの金型になっている。なお、成形方法等によって雄型の代わりに雌型を使用することは任意にできる。
【００１４】
低圧ブロー成形に用いる液体は各種のオイル等、被加工板材１との関連から公知のものを適宜選択使用でき、その液圧は、被加工板材１の材質・板厚・絞り程度等の条件によって一定ではないが、例えば、板厚０．８ｍｍの鉄板を、最大で３００ｍｍ程度絞るとき、２０〜２５ｋｇ／ｃｍ２（平方センチメートル）程度にする。
【００１５】
図１のＢは逐次成形工程であり、Ａにて大まか形状に成形された被加工板材１の周囲をクランプ６により把持し、その一面（図では下面）から治具７を押し当て、他面（図では上面）から棒状押圧部材８を押し当て、被加工板材１と棒状押圧部材８を公知方法により相対移動させることにより、逐次成形によって細部形状９を二次成形する。
【００１６】
このとき被加工板材１と棒状押圧部材８の移動は相対的なものであればよく、被加工板材１を不動に固定し、棒状押圧部材８側をＸＹＺ３軸方向へ自在に移動させるようにしてもよい。また、逆に棒状押圧部材８を固定して被加工板材１側をＸＹＺ３軸方向へ自在に移動させてもよい。さらには被加工板材１と棒状押圧部材８をそれぞれＸＹＺ３軸方向へ自在に移動させてもよい。
【００１７】
逐次成形する細部形状９の部分は、低圧ブロー成形により成形されずに残された部分もしくは不正確な形状部分だけであり、このような部分は、図に例示した比較的深絞りになる凹部や曲率の大きなコーナー部等で被加工板材１が密接せずに浮いてしまうような部分である。
【００１８】
このような部分は低圧ブロー成形における圧力条件によって左右される。したがって、低圧ブロー成形によるコストと、逐次成形によるコスト及び成形時間を考慮して最も有利になるように設定する。いずれにしても逐次成形の対象部分は成形部分全体に対してはかなり小さい範囲となる必要最小限で済むことになる。
【００１９】
次に、本実施例の作用を説明する。上述したように逐次成形に先立って、被加工板材１を低圧ブロー成形にて大まか形状に成形し、その後逐次成形により細部形状９を逐次成形するので、逐次成形を必要最小限にできることになり、成形時間の短縮並びに成形痕を少なくすることができる。しかも低圧ブロー成形はこのような大まか形状の成形を比較的容易かつ低コストに行うができる好適な方法であり、しかも細部まで成形する必要がないので、それ程高圧にする必要がないから、設備を簡単小型化でき、設備費用を低減できる。
【００２０】
また、このような低圧ブロー成形に使用する金型として大まか形状に相当する成形面５を備えた雄型２（又は雌型）を用意すれば足り、しかもその金型は比較的低圧用で足り、かつ成形面５も大まか形状で足りるから金型コストを低減できる。
【００２１】
なお、本願発明は上記実施例に限定されず、同一の発明原理内において種々に変形や応用が可能である。例えば、液圧成形方法は、低圧ブロー成形に限らず、他の適宜公知方法を採用できる。また、逐次成形において治具の代わりに液圧成形の金型を用いてもよい。この場合の金型における成形面は予め細部まで形成しておくようにする。
【図面の簡単な説明】
【図１】実施例方法の原理を示す概念図
【符号の説明】１：被加工板材、２：雄型、３：クランプ、４：液室、５：成形面、６：クランプ、７：治具、８：棒状押圧部材、９：細部形状[0001]
TECHNICAL FIELD OF THE INVENTION
This application relates to a method for forming a sheet material used for sequential forming. Sequential molding is a known method of forming a predetermined three-dimensional shape such as a shell shape by relatively moving a plate member and a pressing member while pressing a rod-shaped or convex or concave-shaped pressing member against a metal thin plate or the like. Say. In the present invention, two orthogonal axes in the plane of the plate material before forming are XY, and the axes perpendicular to these two directions are Z.
[0002]
[Prior art]
Such a sequential molding and apparatus are known from WO 99/38627 and the like. For example, Japanese Patent Application Laid-Open No. 5-42328 discloses that a four-sided plate is horizontally held by wrinkle holding, and a convex pressing is formed from below. Push up the member and pre-draw it into a rough shape, move the plate in the X and Y directions while pressing the rod-shaped pressing member from above, and move the pressing member in the Z direction to form the desired three-dimensional shape. Has become. According to the sequential molding method of Japanese Patent Application No. 2002-040496, there is an advantage that one or both of a male mold and a female mold can be omitted.
[0003]
Another molding method that can omit either the male mold or the female mold is hydraulic molding. Hydraulic molding is a method in which either a male mold or a female mold is used, and a plate material to be processed is pressed into its molding surface with hydraulic pressure to form a predetermined shape. It is a molding method including.
[0004]
Furthermore, the female mold can be omitted even if the tension molding and the sequential molding method are combined. That is, a male mold is pressed against a plate material to be processed gripped by a blank holder to form a rough shape in a short time, and then the detail is formed by a sequential forming method (see Japanese Patent Application No. 2002-043049). .
[0005]
[Problems to be solved by the invention]
In the case of molding by sequential molding alone, it takes a long molding time, and a trace of forming a line by the rod-shaped pressing member remains over a wide area of the surface. In order to accurately form a fine shape only by hydraulic molding, the molding pressure of the liquid must be extremely high, and the equipment becomes complicated, large, and expensive. Further, when the tension molding and the sequential molding method are combined, a high-strength male mold for tension molding must be made, so that the mold cost increases. Accordingly, an object of the present invention is to realize a molding method capable of shortening the molding time and reducing the cost and equipment of the mold while maintaining the advantages of the sequential molding.
[0006]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, a plate material forming method according to claim 1 is a method of forming a plate material using a sequential forming method of forming a predetermined three-dimensional shape by pressing a rod-shaped pressing member against a plate material to be processed and plastically deforming the plate member. In the above method, the plate material to be processed is roughly formed into a rough shape by hydraulic forming, and then details are formed by sequential forming.
[0007]
A second aspect of the present invention is characterized in that, in the first aspect, at the time of the hydroforming, either a male mold or a female mold having a molding surface corresponding to the rough shape is used.
[0008]
A third aspect of the present invention is characterized in that, in the first or second aspect, the hydraulic forming is low-pressure blow molding.
[0009]
【The invention's effect】
According to the first aspect of the present invention, prior to the sequential forming, the plate material to be processed is roughly formed into a shape by hydraulic forming, and then the details are formed by the sequential forming, so that the sequential forming can be minimized. In addition, the molding time can be shortened and molding marks can be reduced. In addition, since it is not necessary to form the liquid pressure molding in detail, it is not necessary to increase the pressure so much, so that the equipment can be simply miniaturized and the equipment cost can be reduced.
[0010]
According to the invention of claim 2, it is sufficient to prepare either a male mold or a female mold having a molding surface corresponding to a rough shape as a mold used for hydroforming, and the mold is relatively Mold pressure can be reduced because a low pressure is sufficient and the molding surface can be roughly formed.
[0011]
According to the third aspect of the present invention, since the hydraulic forming is performed by the low-pressure blow molding, the forming of the plate material to be processed can be performed easily and at low cost.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment will be described with reference to the drawings. FIG. 1 is a conceptual diagram showing a molding method according to the present embodiment. FIG. 1A shows a hydraulic forming step, in which a plate 1 to be processed is placed on a male mold 2, the periphery thereof is fixed with a clamp 3, and a pressure liquid is injected into a liquid chamber 4 to form the plate 1. It is pressed against the surface 5 to form a primary shape roughly like an imaginary line. This molding is a low pressure blow molding.
[0013]
The plate material 1 to be processed is a plate-like material made of an appropriate material such as a metal such as iron that can be subjected to plastic working, and the thickness of the plate material is also appropriately possible.
As the male mold 2, various known materials can be used as long as they have strength necessary for low-pressure blow molding. Further, since the molding surface 5 has a rough shape, it is a low-cost mold as a whole. The use of a female mold instead of a male mold can be arbitrarily used depending on a molding method or the like.
[0014]
The liquid used for the low-pressure blow molding can be appropriately selected and used from various kinds of oil and the like in relation to the plate material 1 to be processed. Although it is not constant, for example, when an iron plate having a thickness of 0.8 mm is squeezed by about 300 mm at the maximum, the thickness is set to about 20 to 25 kg / cm 2 (square centimeter).
[0015]
FIG. 1B shows a sequential forming step, in which the periphery of the plate material 1 roughly formed in A is gripped by the clamp 6, and a jig 7 is pressed from one surface (the lower surface in the figure) to the other surface. By pressing the rod-shaped pressing member 8 from above (the upper surface in the figure) and relatively moving the plate material 1 to be processed and the rod-shaped pressing member 8 by a known method, the detailed shape 9 is secondarily formed by sequential forming.
[0016]
At this time, the movement of the plate material 1 to be processed and the rod-shaped pressing member 8 may be relative as long as the plate material 1 to be processed is fixed immovably and the rod-shaped pressing member 8 side is freely moved in the XYZ three-axis directions. Is also good. Conversely, the rod-shaped pressing member 8 may be fixed and the plate 1 to be processed may be freely moved in the XYZ three-axis directions. Furthermore, the plate material 1 to be processed and the rod-shaped pressing member 8 may be freely moved in the XYZ three-axis directions.
[0017]
The portion of the detailed shape 9 to be sequentially formed is only a portion left without being formed by the low pressure blow molding or an incorrectly formed portion. This is a portion where the plate material 1 to be processed floats without closely contacting at a corner portion or the like having a large curvature.
[0018]
Such a part depends on the pressure conditions in the low pressure blow molding. Therefore, it is set to be most advantageous in consideration of the cost of low-pressure blow molding and the cost and molding time of sequential molding. In any case, the portion to be subjected to the sequential molding is a necessary minimum which is a considerably small range for the entire molded portion.
[0019]
Next, the operation of the present embodiment will be described. As described above, prior to the sequential forming, the workpiece 1 is roughly formed into a rough shape by low-pressure blow molding, and then the detailed shape 9 is sequentially formed by the sequential forming, so that the sequential forming can be minimized. The molding time can be shortened and molding marks can be reduced. In addition, low-pressure blow molding is a suitable method that enables such a rough shape to be formed relatively easily and at low cost.Moreover, since there is no need to mold in detail, it is not necessary to use a high pressure, so equipment is required. Easy downsizing and reduced equipment costs.
[0020]
It is sufficient to prepare a male mold 2 (or a female mold) having a molding surface 5 corresponding to a rough shape as a mold used for such low-pressure blow molding, and the mold is sufficient for relatively low pressure. In addition, since the molding surface 5 needs only to have a rough shape, the die cost can be reduced.
[0021]
It should be noted that the present invention is not limited to the above embodiment, and various modifications and applications are possible within the same principle of the invention. For example, the hydraulic forming method is not limited to the low pressure blow molding, and any other appropriate known method can be adopted. Further, in the successive molding, a mold for hydraulic molding may be used instead of the jig. In this case, the molding surface of the mold is formed in advance to details.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram showing the principle of the method of the embodiment. [Description of symbols] 1: Plate material to be processed, 2: Male type, 3: Clamp, 4: Liquid chamber, 5: Molding surface, 6: Clamp, 7: Cure Tool, 8: rod-shaped pressing member, 9: detailed shape
