JP3727533B2

JP3727533B2 - Molding method for two-layer products

Info

Publication number: JP3727533B2
Application number: JP2000395825A
Authority: JP
Inventors: 功明岩浪
Original assignee: Honda Motor Co Ltd
Current assignee: Honda Motor Co Ltd
Priority date: 2000-12-26
Filing date: 2000-12-26
Publication date: 2005-12-14
Anticipated expiration: 2020-12-26
Also published as: JP2002192245A

Description

【０００１】
【発明の属する技術分野】
本発明は、金属製の製品本体に金属製の板状部品を重ね合わせた２枚重ね製品を成形する方法に関する。
【０００２】
【従来の技術】
従来、この種の２枚重ね製品は、製品本体と板状部品とを別々にプレス成形した後、製品本体に板状部品を溶接等で結合して製造している。
【０００３】
【発明が解決しようとする課題】
上記従来例のものでは、製品本体用と板材部品用の各別のプレス型が必要になり、製品の製造コストが高くなる。そのため、製品本体となる第１の板材に板状部品となる第２の板材を接合して成るブランク材を用い、単一のプレス型で製品をプレス成形することが望まれる。この場合、第１と第２の両板材の外縁部を拘束した状態で両板材を張出し成型することが考えられるが、この方法では、図３（Ｂ）に示す如く、製品本体２と板状部品３との間にスプリングバック量の差に起因して隙間を生ずる。これを詳述するに、張出し成型した板材のスプリングバック量Ｓｂは、板材のヤング率をＥ、曲率半径をｒ、板厚をｈ、降伏強さをｙｐ、加工硬化指数をＮとして、次式、
Ｓｂ＝３（ｙｐ・ｒ／ｈ・Ｅ）／（２＋Ｎ）
で表され、板厚が薄く、成形アール部ｌａにおける曲率半径が板状部品３よりも大きくなる製品本体２のスプリングバック量αの方が板状部品３のスプリングバック量βより大きくなり、製品本体２と板状部品３との間に隙間を生ずる。この隙間には塗装工程で塗料が入りにくく、耐食性が悪くなる。
【０００４】
本発明は、以上の点に鑑み、製品本体と板状部品との間の隙間を生ずることなく、２枚重ね製品を単一のプレス型で成形し得るようにした方法を提供することを課題としている。
【０００５】
【課題を解決するための手段】
上記課題を解決すべく、本発明は、金属製の製品本体に金属製の板状部品を重ね合わせた２枚重ね製品を張出し成形する方法であって、製品本体となる第１の板材の張出方向裏面に、板状部品となる第２の板材であって、第１の板材に較べて面積が小さく、かつ、肉厚が大きい第２の板材を接合して成るブランク材を用い、第１の板材の外縁部を拘束した状態で第１の板材を張出し成形しつつ、第２の板材を非拘束で成形している。
【０００６】
板材を非拘束で成形すると、張出し成形のような材料の伸びを生じないため、成形アール部における成形時の曲げモーメントが大きくなり、その分スプリングバック量も大きくなる。ここで、本発明では、第２の板材、即ち、板状部品を非拘束で成形しているため、板状部品単独でのスプリングバック量は製品本体のスプリングバック量と同等以上になり、製品本体と板状部品との間の隙間の発生が防止される。
【０００７】
【発明の実施の形態】
図１（Ａ）は、自動車のフードのアウタパネルの裏面に取付けるフードインナ１を示している。フードインナ１は、金属製の製品本体２の左右両側部に、フードヒンジの取付部を補強する板状部品３を重ね合わせた２枚重ね製品であり、図１（Ｂ）に示す如く、製品本体２となる比較的薄い第１の板状部材２’に板状部品３となる比較的厚い第２の板材３’を接合して成るブランク材１’を用いて成形される。
【０００８】
その詳細は図２に示す通りであり、先ず、図２（Ａ）に示す如く、下側のパンチ１０と上側のダイ１１とピン１２ａを介して上方に付勢されるブランクホルダ１２とを有するプレス型に、第２の板材３’を下にした状態で第１の板材２’の成形領域の外縁部（スクラップ部）がブランクホルダ１２に着座するようにブランク材１’をセットし、次に、ダイ１１をパンチ１０に向けて下降させる。これによれば、第１の板材２’の外縁部がダイ１１とブランクホルダ１２との間に挟まれて拘束され、この状態でブランク材１’がダイ１１によりブランクホルダ１２と共に押し下げられる。そして、第２の板材３’がパンチ１０に当接したところで第１の板材３’の張出し成形が開始される。
【０００９】
張出し成形の初期段階では、第１の板材２’の第２の板材３’にオーバーラップする部分における変形が規制され、図２（Ｂ）に示す如く、主として第１の板材２’の第２の板材３’にオーバーラップしない部分が変形する。その後、図２（Ｃ）に示す如く、第２の板材３’も変形し、最終的に、図２（Ｄ）に示す如く、ブランク材１’がパンチ１０とダイ１１との間に挟まれて、第１と第２の両板材２’，３’が夫々パンチ１０とダイ１１に合致する所要の形状に成形される。そして、成形後、第１の板材２’の外縁部（スクラップ部）をトリミング加工で除去し、フードインナ１を得る。
【００１０】
ここで、第２の板材３’の外縁部はブランクホルダ１２とダイ１１との間に挟まれておらず、第２の板材３’は非拘束で材料の伸びを生ずることなく成形される。そのため、製品の成形アール部ｌａにおける板状部品３の成形時の曲げモーメントが大きくなり、その分スプリングバック量も大きくなる。ところで、第２の板材３’を第１の板材２’の外縁部に達する幅広のものとし、第２の板材３’もその外縁部を拘束した状態で張出し成形した場合、図３（Ｂ）に示す如く、板厚が薄く、且つ、成形アール部ｌａにおける曲率半径が大きくなる製品本体２のスプリングバック量αの方が板状部品３のスプリングバック量βより大きくなり、製品本体２と板状部品３との間に隙間を生ずる。これに対し、本実施形態では、板状部品３単独でのスプリングバック量が製品本体２のスプリングバック量αと同等以上になり、図３（Ａ）に示す如く板状部品３が製品本体２と同等にスプリングバックし、製品本体２と板状部品３との間の隙間の発生が防止される。
【００１１】
また、ブランク材１’の製造に際し、第２の板材３’の一部分を第１の板材２’にスポット溶接で接合することも考えられるが、本実施形態では、図４に示す如く、第２の板材３’の一部分を接着テープ４で第１の板材２’に接着し、第２の板材３’の残りの部分と第１の板材２’との間に０．０５〜０．１ｍｍ程度の隙間が形成されるようにしている。また、図５に示すように、第２の板材３’をコイル材から打抜くせん断工程で第２の板材３’に生ずるバリ３’ａの発生面とは反対側の面を第１の板材２’に対する接着面としている。ここで、第２の板材３’のバリ３’ａの発生面とは反対側の面の外縁部はダレ３’ｂを生じている。そのため、第１の板材２’の張出し成形の初期段階で第１の板材２’の第２の板材３’にオーバーラップしない部分が変形する際に、第１の板材２’が図５に示す如くダレ３’ｂの部分で緩やかに湾曲し、第１の板材２’の第２の板材３’の外縁に合致する部分における応力集中が緩和される。従って、この応力集中に起因する第１の板材２’の傷や亀裂の発生が効果的に防止される。
【００１２】
また、第１の板材２’は最終的に第２の板材３’に密着するが、成形途中までは接着テープ４と第２の板材３’の外縁との間の範囲で第１と第２の両板材２’，３’間に隙間が残っている。そのため、第１の板材２’の第２の板材３’にオーバーラップする部分に第２の板材３’との接触で作用する張出し成形時の摩擦力が減少し、オーバーラップ部分での伸びを生じ易くなる。かくて、第１の板材２’が第２の板材３’にオーバーラップしない部分からオーバーラップする部分に亘って均等に伸びるようになる。従って、第１の板材２’が第２の板材３’にオーバーラップしない部分で過度に伸びることはなく、製品本体２の強度低下が防止される。
【００１３】
以上、フードインナ１の成形に本発明を適用した実施形態について説明したが、フードインナ以外の２枚重ね製品の成形にも同様に本発明を適用できる。尚、フードインナ１では、製品本体２と板状部品３との重ね合わせ部に後加工でヒンジ取付ボルトを挿通する穴を明け、板状部品３側からヒンジ取付ボルトにナットを締め込むため、製品本体２に板状部品３を強固に結合しておく必要はないが、製品本体に対する板状部品の結合強度を必要とする製品については、第２の板材を第１の板材に部分接着したブランク材を用いて製品を成形した後、板状部品を製品本体にスポット溶接すれば良い。また、上記実施形態では、第２の板材３’として厚板を用いたが、第２の板材を第１の板材と同じ薄板とする場合にも同様に本発明を適用できる。
【００１４】
【発明の効果】
以上の説明から明らかなように、本発明によれば、２枚重ね製品を製品本体と板状部品との間の隙間を生ずることなく単一のプレス型で成形でき、コストダウンを図れる。
【図面の簡単な説明】
【図１】（Ａ）本発明方法で成形する２枚重ね製品の一例を示す斜視図、（Ｂ）この製品の成形に用いるブランク材を示す斜視図。
【図２】（Ａ）プレス型へのブランク材のセット状態を示す要部の断面図、（Ｂ）成形初期段階の要部の断面図、（Ｃ）成形中間段階の要部の断面図、（Ｄ）成形最終段階の要部の断面図。
【図３】（Ａ）本発明方法による成形後の製品の要部の断面図、（Ｂ）第２の板材も張出し成形したときの製品の要部の断面図。
【図４】成形前のブランク材の要部の断面図。
【図５】成形中のブランク材の要部の拡大断面図。
【符号の説明】
１…フードインナ（２枚重ね製品）
１’…ブランク材
２…製品本体
２’…第１の板材
３…板状部品
３’…第２の板材
１０…パンチ
１１…ダイ
１２…ブランクホルダ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method of forming a two-layer product in which metal plate-like parts are superimposed on a metal product body.
[0002]
[Prior art]
Conventionally, this type of two-ply product is manufactured by press-molding a product body and a plate-like component separately, and then joining the plate-like component to the product body by welding or the like.
[0003]
[Problems to be solved by the invention]
In the above-described conventional example, separate press dies for the product main body and the plate material parts are required, which increases the manufacturing cost of the product. For this reason, it is desired to use a blank material formed by joining a second plate material to be a plate-like component to a first plate material to be a product main body, and press-mold the product with a single press die. In this case, it is conceivable that the both plate materials are stretched and molded while the outer edge portions of both the first and second plate materials are constrained. In this method, as shown in FIG. A gap is generated between the part 3 and the part 3 due to the difference in the amount of springback. To explain this in detail, the springback amount Sb of the stretched plate material is expressed by the following equation, where the Young's modulus of the plate material is E, the radius of curvature is r, the plate thickness is h, the yield strength is yp, and the work hardening index is N. ,
Sb = 3 (yp · r / h · E) / (2 + N)
The spring back amount α of the product body 2 in which the plate thickness is thin and the radius of curvature at the forming radius portion la is larger than that of the plate-like component 3 is larger than the spring back amount β of the plate-like component 3, A gap is created between the main body 2 and the plate-like component 3. Paints are difficult to enter in the gaps in the painting process, and the corrosion resistance deteriorates.
[0004]
In view of the above, the present invention has an object to provide a method in which a two-ply product can be formed with a single press die without causing a gap between the product main body and the plate-like component. It is said.
[0005]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention is a method of stretch- molding a two-layer product in which a metal plate-like component is superimposed on a metal product body, and the first plate material serving as the product body is stretched . Using a blank material formed by joining a second plate material , which is a plate-shaped component , on the rear surface in the outgoing direction, the second plate material having a smaller area and a larger thickness than the first plate material, The second plate material is formed unconstrained while the first plate material is stretched and formed while the outer edge portion of the first plate material is constrained.
[0006]
If the plate material is formed without restraint, the material does not stretch as in the case of stretch forming, so the bending moment at the time of forming in the forming round portion increases, and the amount of spring back increases accordingly. Here, in the present invention, since the second plate material, that is, the plate-like component is formed without restraint, the springback amount of the plate-like component alone is equal to or more than the springback amount of the product body, and the product Generation of a gap between the main body and the plate-like component is prevented.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1A shows a hood inner 1 attached to the back surface of an outer panel of an automobile hood. The hood inner 1 is a two-ply product in which plate-like parts 3 that reinforce the attachment part of the hood hinge are superimposed on the left and right sides of a metal product body 2, and as shown in FIG. It is molded using a blank 1 ′ formed by joining a relatively thin second plate 3 ′ to be a plate-like component 3 to a relatively thin first plate 2 ′ to be a main body 2.
[0008]
The details are as shown in FIG. 2. First, as shown in FIG. 2 (A), it has a lower punch 10, an upper die 11, and a blank holder 12 biased upward via a pin 12a. The blank 1 ′ is set on the press die so that the outer edge (scrap part) of the molding region of the first plate 2 ′ is seated on the blank holder 12 with the second plate 3 ′ facing down. Next, the die 11 is lowered toward the punch 10. According to this, the outer edge part of 1st board | plate material 2 'is pinched | interposed and restrained between the die | dye 11 and the blank holder 12, and blank material 1' is pushed down with the blank holder 12 by the die | dye 11 in this state. Then, when the second plate material 3 ′ comes into contact with the punch 10, overhang forming of the first plate material 3 ′ is started.
[0009]
In the initial stage of the overhang forming, the deformation of the portion of the first plate member 2 ′ that overlaps the second plate member 3 ′ is restricted, and as shown in FIG. 2 (B), mainly the second plate of the first plate member 2 ′. The portion that does not overlap the plate material 3 ′ is deformed. Thereafter, as shown in FIG. 2C, the second plate 3 ′ is also deformed, and finally, as shown in FIG. 2D, the blank 1 ′ is sandwiched between the punch 10 and the die 11. Thus, both the first and second plate members 2 ′ and 3 ′ are formed into required shapes that match the punch 10 and the die 11, respectively. And after shaping | molding, the outer edge part (scrap part) of 1st board | plate material 2 'is removed by trimming, and the food inner 1 is obtained.
[0010]
Here, the outer edge portion of the second plate member 3 ′ is not sandwiched between the blank holder 12 and the die 11, and the second plate member 3 ′ is formed without any restraint and without stretching of the material. Therefore, the bending moment at the time of molding of the plate-like component 3 in the molded round portion la of the product increases, and the amount of spring back increases accordingly. By the way, when the second plate 3 'is wide enough to reach the outer edge of the first plate 2', and the second plate 3 'is also stretched and formed with the outer edge constrained, FIG. As shown in FIG. 4, the spring back amount α of the product body 2 in which the plate thickness is thin and the radius of curvature at the forming radius portion la is larger than the spring back amount β of the plate-like component 3, and the product body 2 and the plate A gap is formed between the cylindrical part 3 and the like part 3. On the other hand, in the present embodiment, the amount of springback of the plate-like component 3 alone is equal to or greater than the amount of springback α of the product main body 2, and the plate-like component 3 is replaced by the product main body 2 as shown in FIG. And the occurrence of a gap between the product body 2 and the plate-like component 3 is prevented.
[0011]
Further, in manufacturing the blank material 1 ′, it is conceivable to join a part of the second plate material 3 ′ to the first plate material 2 ′ by spot welding, but in this embodiment, as shown in FIG. A portion of the plate material 3 ′ is adhered to the first plate material 2 ′ with the adhesive tape 4, and the remaining portion of the second plate material 3 ′ and the first plate material 2 ′ are about 0.05 to 0.1 mm. The gap is formed. Further, as shown in FIG. 5, the surface opposite to the generation surface of the burr 3′a generated in the second plate 3 ′ in the shearing process of punching the second plate 3 ′ from the coil material is the first plate. Adhesive surface for 2 '. Here, the outer edge portion of the surface opposite to the generation surface of the burr 3′a of the second plate member 3 ′ generates a sag 3′b. Therefore, when the portion of the first plate 2 'that does not overlap the second plate 3' is deformed in the initial stage of the overhang forming of the first plate 2 ', the first plate 2' is shown in FIG. As described above, the sag 3'b is gently curved, and the stress concentration in the portion of the first plate 2 'matching the outer edge of the second plate 3' is alleviated. Therefore, the occurrence of scratches and cracks in the first plate member 2 ′ due to this stress concentration is effectively prevented.
[0012]
The first plate 2 'is finally in close contact with the second plate 3', but the first and second are in the range between the adhesive tape 4 and the outer edge of the second plate 3 'until the middle of molding. A gap remains between the two plate members 2 'and 3'. For this reason, the frictional force at the time of overhang forming which acts on the portion of the first plate member 2 ′ overlapping with the second plate member 3 ′ by contact with the second plate member 3 ′ is reduced, and the elongation at the overlap portion is increased. It tends to occur. Thus, the first plate 2 'extends evenly from the portion that does not overlap the second plate 3' to the portion that overlaps. Accordingly, the first plate member 2 ′ does not extend excessively at a portion where it does not overlap the second plate member 3 ′, and the strength of the product body 2 is prevented from being reduced.
[0013]
As mentioned above, although embodiment which applied this invention to shaping | molding of the food inner 1 was described, this invention can be applied similarly to shaping | molding of two-ply products other than food inner. In the hood inner 1, a hole for inserting the hinge mounting bolt is formed in the overlap portion of the product main body 2 and the plate-like component 3 by post-processing, and a nut is tightened on the hinge mounting bolt from the plate-like component 3 side. Although it is not necessary to firmly bond the plate-like component 3 to the product body 2, the second plate material is partially bonded to the first plate material for products that require the bonding strength of the plate-like component to the product body. After forming the product using the blank material, the plate-like component may be spot welded to the product body. Moreover, in the said embodiment, although the thick board was used as 2nd board | plate material 3 ', this invention is applicable similarly, when making a 2nd board | plate material the same thin plate as a 1st board | plate material.
[0014]
【The invention's effect】
As is apparent from the above description, according to the present invention, a two-ply product can be formed with a single press die without generating a gap between the product main body and the plate-like component, and the cost can be reduced.
[Brief description of the drawings]
FIG. 1A is a perspective view showing an example of a two-ply product formed by the method of the present invention, and FIG. 1B is a perspective view showing a blank material used for forming this product.
2A is a cross-sectional view of a main part showing a set state of a blank material on a press die, FIG. 2B is a cross-sectional view of a main part in an initial stage of molding, and FIG. (D) Sectional drawing of the principal part of a shaping | molding final stage.
3A is a cross-sectional view of a main part of a product after molding by the method of the present invention, and FIG. 3B is a cross-sectional view of a main part of the product when a second plate material is also stretched.
FIG. 4 is a cross-sectional view of a main part of a blank material before molding.
FIG. 5 is an enlarged cross-sectional view of a main part of a blank material being molded.
[Explanation of symbols]
1 ... food inner (two-layer product)
DESCRIPTION OF SYMBOLS 1 '... Blank material 2 ... Product main body 2' ... 1st board | plate material 3 ... Plate-shaped component 3 '... 2nd board | plate material 10 ... Punch 11 ... Die 12 ... Blank holder

Claims

金属製の製品本体に金属製の板状部品を重ね合わせた２枚重ね製品を張出し成形する方法であって、製品本体となる第１の板材の張出方向裏面に、板状部品となる第２の板材であって、第１の板材に較べて面積が小さく、かつ、肉厚が大きい第２の板材を接合して成るブランク材を用い、第１の板材の外縁部を拘束した状態で第１の板材を張出し成形しつつ、第２の板材を非拘束で成形する、ことを特徴とする２枚重ね製品の成形方法。A method of overhanging a two-ply product in which a metal plate-like component is superimposed on a metal product body, wherein the plate-like component is formed on the back surface of the first plate material that is the product body. 2 using a blank material formed by joining a second plate material having a smaller area and a larger thickness than the first plate material, with the outer edge portion of the first plate material restrained. A method for forming a two-ply product, characterized in that the second plate is formed unconstrained while the first plate is stretched.