JP2021159951A - Method for manufacturing sheet-metal-formed product, device for manufacturing sheet-metal-formed product, and tool for flange-up - Google Patents

Method for manufacturing sheet-metal-formed product, device for manufacturing sheet-metal-formed product, and tool for flange-up Download PDF

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JP2021159951A
JP2021159951A JP2020064322A JP2020064322A JP2021159951A JP 2021159951 A JP2021159951 A JP 2021159951A JP 2020064322 A JP2020064322 A JP 2020064322A JP 2020064322 A JP2020064322 A JP 2020064322A JP 2021159951 A JP2021159951 A JP 2021159951A
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flange
curvature
tool
sheet metal
molded product
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JP7364905B2 (en
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聡 白神
Satoshi Shiragami
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Nippon Steel Corp
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Abstract

To provide a tool having a relatively simple shape within the range of conventional mold structures, that can suppress occurrence of cracks in a flange portion of a press-formed product when used.SOLUTION: A method for manufacturing a press-formed-product having a flange portion comprises: a flange-up step of forming the flange portion on a blank to obtain a preformed product; and a re-strike step of re-striking the preformed product into a press-formed product having a target shape. The method uses in the flange-up step, a punch which is constituted of large curvature portions having curvatures larger than curvatures of curvature portions constituting a tool used in the re-strike step, and a small curvature portion sandwiched between the large curvature portions and having a curvature smaller than the curvatures of the curvature portions constituting the tool used in the re-strike step, and which has a length of a curved portion short.SELECTED DRAWING: Figure 2

Description

本発明は、板金成形品の製造方法、板金成形品の製造装置、及びフランジアップ工具に関し、特に、B型伸びフランジ変形を受ける湾曲フランジ部(以下、単に「フランジ部」ともいう)を有する板金成形品の製造方法、板金成形品の製造装置、及びフランジアップ工具に関する。 The present invention relates to a method for manufacturing a sheet metal molded product, a sheet metal molded product manufacturing apparatus, and a flange-up tool, and in particular, a sheet metal having a curved flange portion (hereinafter, also simply referred to as “flange portion”) that is subject to B-shaped stretch flange deformation. The present invention relates to a method for manufacturing a molded product, a manufacturing apparatus for a sheet metal molded product, and a flange-up tool.

近年、環境負荷低減を目的とした車体軽量化と衝突安全性の両立に加え、乗り心地の観点から車体の高剛性化が求められている。そのため、車体骨格部材には、高強度鋼板が適用されることが多くなるとともに、締結フランジの高さ向上や連続化のような複雑な形状を要求されることがあり、このような形状ではフランジ部は伸びフランジ変形を受ける場合がある。 In recent years, in addition to both weight reduction of the vehicle body and collision safety for the purpose of reducing the environmental load, high rigidity of the vehicle body has been required from the viewpoint of riding comfort. Therefore, high-strength steel plates are often applied to the vehicle body skeleton members, and complicated shapes such as improvement of the height of the fastening flange and continuity may be required. In such a shape, the flange is used. The part may be deformed by an extension flange.

一般的に、車体骨格部材は金属板のプレス成形によって量産される。伸びフランジ変形は、あらかじめ打ち抜き加工や切削加工により所定形状とされたブランクの面部を拘束し、周辺部を、曲げ稜線がブランクの面内方向に凹形状となるように、ブランクの面外方向に曲げながら引き延ばす加工を施した場合に、成形されたフランジに生じる変形である。これにより、ブランク面外方向に突き出し、ブランクの面内方向に凹形状を有する曲げ稜線に沿って湾曲したフランジが成形される。 Generally, the vehicle body skeleton member is mass-produced by press molding of a metal plate. The stretch flange deformation restrains the surface portion of the blank that has been formed into a predetermined shape by punching or cutting in advance, and makes the peripheral portion in the out-of-plane direction of the blank so that the bending ridge line becomes concave in the in-plane direction of the blank. This is a deformation that occurs in a molded flange when it is stretched while being bent. As a result, a flange that protrudes outward from the blank surface and is curved along a bent ridge line having a concave shape in the in-plane direction of the blank is formed.

一般的に、伸びフランジ変形を受けるフランジの板厚は、湾曲部頂点付近で最も薄く、次いでこの領域に近い領域ほど薄くなる。このような現象は、これらの領域で伸びフランジ成形時の加工度が大きく、ひいては変形が大きいためである。そのため、加工前の加工部位を伸びフランジ成形によって、所定のフランジに成形する際に、特に、フランジの湾曲部頂点付近で割れが生ずることがある。伸びフランジ割れは、金属板が高強度化すると、特に問題となる。 In general, the plate thickness of the flange subject to the stretch flange deformation is the thinnest near the apex of the curved portion, and then becomes thinner in the region closer to this region. This phenomenon is due to the large degree of processing during stretch flange molding in these regions, which in turn results in large deformation. Therefore, when the processed portion before processing is formed into a predetermined flange by stretch flange molding, cracks may occur particularly near the apex of the curved portion of the flange. Stretch flange cracking becomes a particular problem when the strength of the metal plate is increased.

伸びフランジ割れが発生した場合には、フランジ高さを小さくする、又は、フランジの湾曲部そのものを切欠き除去することが考えられる。しかしながら、フランジは、通常、部品と部品を締結するために設置されているため、このような対策を施した場合、車体剛性を著しく損なう恐れがある。 When a stretch flange crack occurs, it is conceivable to reduce the flange height or remove the curved portion of the flange itself by notching. However, since the flange is usually installed to fasten the parts to each other, if such measures are taken, the rigidity of the vehicle body may be significantly impaired.

そこで、伸びフランジ成形に用いる工具の形状を改良することにより、伸びフランジ割れを防止する、フランジ付成形部材の加工技術について、種々の提案がなされている。 Therefore, various proposals have been made for processing techniques for flanged molded members that prevent stretch flange cracking by improving the shape of the tool used for stretch flange molding.

特許文献1は、コーナーフランジ部を一工程で成形することができ、伸び変形によるコーナー中心及びその近傍でのひずみの局在化を抑制して伸びフランジ割れを防止し、品質と生産性を両立可能なプレス成形型を提供することを課題とし、ダイコーナー部を有するダイと、パンチコーナー部を有するパンチとを備え、パンチコーナー部は、ストローク方向の先端面において、コーナー中心の両側の2つの弧状凸部の間に凹部を有する輪郭形状であり、先端面と平行な断面の輪郭形状は、断面が先端面から離れるにつれて凹部が小さくなると共に2つの弧状凸部が接近して外向きコーナー形状に収束するプレス成形型を開示している。 Patent Document 1 can form a corner flange portion in one step, suppresses localization of strain in and near the center of a corner due to elongation deformation, prevents elongation flange cracking, and achieves both quality and productivity. An object of the present invention is to provide a possible press molding die, which comprises a die having a die corner portion and a punch having a punch corner portion, and the punch corner portion has two punch corner portions on both sides of the center of the corner on the tip surface in the stroke direction. It is a contour shape with recesses between the arc-shaped protrusions, and the contour shape of the cross section parallel to the tip surface is such that the recesses become smaller as the cross section moves away from the tip surface and the two arc-shaped protrusions approach each other to form an outward corner shape. The press molding mold that converges to is disclosed.

特開2017−148847号公報JP-A-2017-148847

特許文献1の技術によれば、コーナーフランジ部を一工程で成形することができるが、金型の高さが大きくなり、従来のプレス成形装置を用いようとした場合、クッションストロークの変更等が必要となる。さらに、高さが著しく大きくなる場合は、ダイハイトの大きいプレス機への変更が必要となる。 According to the technique of Patent Document 1, the corner flange portion can be molded in one step, but the height of the mold becomes large, and when a conventional press molding apparatus is used, the cushion stroke may be changed. You will need it. Furthermore, if the height becomes significantly large, it is necessary to change to a press machine with a large die height.

金型の観点からは、金型製作コスト、メンテナンス性、スペース制約から、構造が簡易であり、かつサイズが小さいことが求められる。すなわち、従来のプレス成形装置に、金型サイズを拡大することなく適用可能な技術が求められている。 From the viewpoint of the mold, it is required that the structure is simple and the size is small from the viewpoint of mold manufacturing cost, maintainability, and space limitation. That is, there is a demand for a technique that can be applied to a conventional press molding apparatus without increasing the mold size.

本発明は上記事情に鑑みてなされたものであって、ブランクの面外方向に突き出し、ブランクの面内方向に凹形状を有する曲げ稜線に沿って湾曲するフランジを対象とし、従来の金型構造の範囲の比較的単純な形状で構成された工具を用いて、フランジ部に導入される変形量を低減することで割れの発生を抑制することを課題とする。 The present invention has been made in view of the above circumstances, and is intended for a flange that protrudes in the out-of-plane direction of the blank and curves along a bending ridge having a concave shape in the in-plane direction of the blank, and has a conventional mold structure. It is an object of the present invention to suppress the occurrence of cracks by reducing the amount of deformation introduced into the flange portion by using a tool having a relatively simple shape in the range of.

本発明者らは、ブランクの面外方向に突き出し、湾曲するフランジの整形において、従来の金型構造の範囲の比較的単純な形状で構成された工具を用いて、フランジ部に導入される変形量を低減することで割れの発生を抑制する方法について鋭意検討した。 The present inventors introduce deformations introduced into the flange portion in shaping a flange that protrudes in the out-of-plane direction of the blank and is curved by using a tool having a relatively simple shape within the range of the conventional mold structure. We diligently studied a method of suppressing the occurrence of cracks by reducing the amount.

その結果、フランジ成形をフランジアップ工程とリストライク工程の2工程に分け、それぞれの工程で異なる工具を用い、フランジアップ工程工具の曲率部をリストライク工程工具の曲率部よりも大きい曲率を有する曲率部とこれらに挟まれる直線部で構成し、さらに、フランジアップ工程工具の製品のフランジ部に対応する凸状部の線長を短くすることで、割れが発生する危険性の高い、ひずみ量が最大となる部位近傍におけるひずみ分布が平坦化され、ひずみ量の最大値を小さくし、伸びフランジ割れを生じさせることなく所望の曲率および高さの連続したフランジを成形することができることを見出した。ここで、「工具」とは、「パンチ」と「ダイ」の一方、又は両方をいう。 As a result, flange forming is divided into two processes, a flange-up process and a rest-like process, and different tools are used in each process, and the curvature of the flange-up process tool has a curvature larger than that of the rest-like process tool. It is composed of a part and a straight part sandwiched between them, and by shortening the line length of the convex part corresponding to the flange part of the product of the flange-up process tool, the amount of strain with a high risk of cracking can be reduced. It has been found that the strain distribution in the vicinity of the maximum portion is flattened, the maximum value of the strain amount is reduced, and a continuous flange having a desired curvature and height can be formed without causing stretch flange cracking. Here, the "tool" refers to one or both of a "punch" and a "die".

本発明は、上記の知見に基づき、さらに検討を進めてなされたものであって、その要旨は以下のとおりである。 The present invention has been further studied based on the above findings, and the gist thereof is as follows.

(1)外周縁の一部が内方に向かって突出した凹状外周縁部を有する天板部と、前記凹状外周縁部から連続して内方に向かって湾曲するフランジ部とを備えた板金成形品の製造方法であって、ブランクに前記フランジ部を形成し予成形品を得るフランジアップ工程と、前記予成形品を目標形状の板金成形品にリストライクするリストライク工程を備え、平面視で、前記予成形品の前記フランジ部は、前記板金成形品の前記フランジ部を構成する曲率部の曲率よりも大きい曲率を有する2つの大曲率部と、これらに挟まれる前記板金成形品の前記フランジ部を構成する曲率部の曲率よりも小さい曲率を有する小曲率部で構成され、前記予成形品の前記フランジ部は、平面視における線長が、前記板金成形品の前記フランジ部の平面視における線長と比較して短いことを特徴とする板金成形品の製造方法。 (1) A sheet metal having a top plate portion having a concave outer peripheral edge portion in which a part of the outer peripheral edge protrudes inward, and a flange portion continuously curved inward from the concave outer peripheral edge portion. A method for manufacturing a molded product, which includes a flange-up step of forming the flange portion on a blank to obtain a preformed product and a rest-like step of relisting the preformed product to a sheet metal molded product having a target shape. The flange portion of the preformed product has two large curvature portions having a curvature larger than the curvature of the curvature portion constituting the flange portion of the sheet metal molded product, and the sheet metal molded product sandwiched between the two large curvature portions. The flange portion of the preformed product is composed of a small curvature portion having a curvature smaller than the curvature of the curvature portion constituting the flange portion, and the line length in the plan view is the plan view of the flange portion of the sheet metal molded product. A method for manufacturing a sheet metal molded product, which is characterized in that it is shorter than the wire length in the above.

(2)前記小曲率部は、平面視で直線部であることを特徴とする前記(1)の板金成形品の製造方法。 (2) The method for manufacturing a sheet metal molded product according to (1), wherein the small curvature portion is a straight portion in a plan view.

(3)外周縁の一部が内方に向かって突出した凹状外周縁部を有する天板部と、前記凹状外周縁部から連続して内方に向かって湾曲するフランジ部とを備えた板金成形品を製造する板金成形品の製造装置であって、前記凹状外周縁部に対応する凸状部を有するフランジアップ用工具、前記凹状外周縁部に対応する凸状部を有するリストライク用工具を備え、前記フランジアップ用工具の凸状部は、平面視で、前記リストライク用工具の凸状部を構成する曲率部の曲率よりも大きい曲率を有する2つの大曲率部と、これらに挟まれる前記板金成形品の前記リストライク用工具の凸状部を構成する曲率部の曲率よりも小さい曲率を有する小曲率部で構成され、前記フランジアップ用工具の凸状部は、平面視における線長が、前記リストライク用工具の凸状部の平面視における線長と比較して短いことを特徴とする板金成形品の製造装置。 (3) A sheet metal having a top plate portion having a concave outer peripheral edge portion in which a part of the outer peripheral edge protrudes inward, and a flange portion continuously curved inward from the concave outer peripheral edge portion. A device for manufacturing a sheet metal molded product for manufacturing a molded product, which is a flange-up tool having a convex portion corresponding to the concave outer peripheral edge portion, and a wrist-like tool having a convex portion corresponding to the concave outer peripheral edge portion. The convex portion of the flange-up tool is sandwiched between two large curvature portions having a curvature larger than the curvature of the curvature portion constituting the convex portion of the restorative tool in a plan view. The convex portion of the flange-up tool is formed by a small curvature portion having a curvature smaller than the curvature of the curvature portion constituting the convex portion of the rest-like tool of the sheet metal molded product, and the convex portion of the flange-up tool is a line in a plan view. An apparatus for manufacturing a sheet metal molded product, characterized in that the length is shorter than the line length in a plan view of the convex portion of the wrist-like tool.

(4)前記小曲率部は、平面視で直線であることを特徴とする前記(3)の板金成形品の製造装置。 (4) The apparatus for manufacturing a sheet metal molded product according to (3), wherein the small curvature portion is a straight line in a plan view.

(5)前記(3)の板金成形品の製造装置に用いるフランジアップ用工具であって、板金成形品にフランジを形成するための凸状部を備え、前記凸状部は、平面視で、2つの大曲率部、及び前記2つの大曲率部に挟まれる、前記大曲率部よりも曲率が小さい小曲率部を有することを特徴とするフランジアップ用工具。 (5) A flange-up tool used in the apparatus for manufacturing a sheet metal molded product according to (3), which is provided with a convex portion for forming a flange on the sheet metal molded product, and the convex portion is viewed in a plan view. A flange-up tool having two large curvature portions and a small curvature portion sandwiched between the two large curvature portions and having a smaller curvature than the large curvature portion.

(6)前記小曲率部は、平面視で直線であることを特徴とする前記(5)のフランジアップ用工具。 (6) The flange-up tool according to (5), wherein the small curvature portion is a straight line in a plan view.

本発明によれば、従来の金型構造の範囲の比較的単純な形状で構成された工具を用いて、フランジ部に導入される変形量を低減することで割れの発生を抑制することができる。 According to the present invention, it is possible to suppress the occurrence of cracks by reducing the amount of deformation introduced into the flange portion by using a tool having a relatively simple shape within the range of the conventional mold structure. ..

本発明の板金成形品の製造方法に用いる工具の正面方向上方からの斜視図である。It is a perspective view from the front direction upper side of the tool used in the manufacturing method of the sheet metal molded article of this invention. フランジアップ工程工具の凸状部、リストライク工程工具の凸状部を拡大し、重ねて描いた図である。It is the figure which enlarged and overlapped the convex part of the flange-up process tool and the convex part of the rest-like process tool. パンチ、ダイ、ブランクホルダーを用いて、ブランクを伸びフランジ成形する際の模式図である。It is a schematic diagram at the time of stretching flange molding of a blank using a punch, a die, and a blank holder. 本発明の板金成形品の製造方法におけるフランジ周方向のひずみ分布と、従来技術による板金成形品の製造方法におけるフランジ周方向のひずみ分布を比較した図である。It is a figure which compared the strain distribution in the flange circumferential direction in the manufacturing method of a sheet metal molded article of this invention, and the strain distribution in a flange circumferential direction in the manufacturing method of a sheet metal molded article by a prior art. フランジアップ用工具の形状を説明する図である。It is a figure explaining the shape of the flange-up tool. フランジアップ用工具の形状とひずみの最大値の関係を示す図である。It is a figure which shows the relationship between the shape of the flange-up tool and the maximum value of strain.

以下に、本実施形態に係る板金成形品の製造方法及び板金成形品の製造装置について、詳細に説明する。 Hereinafter, the method for manufacturing the sheet metal molded product and the apparatus for manufacturing the sheet metal molded product according to the present embodiment will be described in detail.

図1は本実施形態に係る板金成形品の製造方法に用いる工具の正面方向上方からの斜視図であり、図2は工具の凸状部(図1のA)を平面視した拡大図であり、フランジアップ用工具の曲率部21、リストライク用工具の曲率部26を重ねて描いたものである。 FIG. 1 is a perspective view from above in the front direction of the tool used in the method for manufacturing a sheet metal molded product according to the present embodiment, and FIG. 2 is an enlarged view of a convex portion (A in FIG. 1) of the tool in a plan view. , The curved portion 21 of the flange-up tool and the curved portion 26 of the wrist-like tool are drawn in an overlapping manner.

フランジアップ工程工具とリストライク工程工具は、おおまかには近い形状であるが、図2に示すように、フランジアップ用工具の凸状部は、平面視でリストライク用工具の凸状部を構成する曲率部よりも大きい曲率を有する大曲率部とこれらに挟まれるリストライク用工具の凸状部を構成する曲率部よりも小さい曲率を有する小曲率部で構成されており、また、フランジアップ用工具の凸状部は、平面視における線長が、リストライク用工具の凸状部の平面視における線長と比較して短くなっている。小曲率部は曲率ゼロ、すなわち、直線であってもよい。 The flange-up process tool and the wrist-like process tool have roughly similar shapes, but as shown in FIG. 2, the convex portion of the flange-up process tool constitutes the convex portion of the wrist-like tool in a plan view. It is composed of a large curvature part having a curvature larger than the curvature part to be formed and a small curvature part having a curvature smaller than the curvature part forming the convex part of the restorative tool sandwiched between them, and for flange up. The line length of the convex portion of the tool in a plan view is shorter than the line length of the convex portion of the wrist-like tool in a plan view. The small curvature portion may have zero curvature, that is, a straight line.

図2の例では、リストライク用工具の凸状部を構成する曲率部が1つであるのに対し、フランジアップ用工具の凸状部は、リストライク用工具の凸状部を構成する曲率部と比較して曲率が大きい2つの大曲率部を有し、平面視で、2つの大曲率部22が、小曲率部である直線部23で結ばれている。図2の例では、この直線部23は、リストライク用工具と重ねると、平面視で、リストライク用工具の凸状部を構成する曲率部の内側を通るので、フランジアップ用工具の凸状部は、平面視における線長が、リストライク用工具の凸状部の平面視における線長と比較して短くなっている。 In the example of FIG. 2, there is only one curvature portion forming the convex portion of the wrist-like tool, whereas the convex portion of the flange-up tool has the curvature forming the convex portion of the wrist-like tool. It has two large curvature portions having a larger curvature than the portions, and in a plan view, the two large curvature portions 22 are connected by a straight portion 23 which is a small curvature portion. In the example of FIG. 2, when the straight portion 23 is overlapped with the wrist-like tool, it passes through the inside of the curved portion constituting the convex portion of the wrist-like tool in a plan view, so that the convex shape of the flange-up tool is formed. The line length of the portion in the plan view is shorter than the line length in the plan view of the convex portion of the wrist-like tool.

以上に示す成形工具を用いた伸びフランジ成形は、たとえば、以下のように行う。 Stretch flange molding using the molding tools shown above is performed, for example, as follows.

図3はダイ31、パンチ32、ブランクホルダー33を用いて、ブランク34を伸びフランジ成形する例を示す模式図である。同図に示す例では、ダイ31とブランクホルダー33とによりブランク34を挟んだ状態で、ブランク34の端部をパンチ32の上面に乗せる。次いで、ダイ31を鉛直方向下方に引き下げて伸びフランジ成形を行い、天板部とフランジ部を有する板金成形品を製造する。なお、ブランクホルダーはダイスと共にブランクを挟み込むためのものであるが、ブランクホルダー無しでプレス成形を行うことも可能である。 FIG. 3 is a schematic view showing an example in which a blank 34 is stretched and flanged using a die 31, a punch 32, and a blank holder 33. In the example shown in the figure, the end portion of the blank 34 is placed on the upper surface of the punch 32 with the blank 34 sandwiched between the die 31 and the blank holder 33. Next, the die 31 is pulled downward in the vertical direction to perform stretch flange molding, and a sheet metal molded product having a top plate portion and a flange portion is manufactured. The blank holder is for sandwiching the blank together with the die, but it is also possible to perform press molding without the blank holder.

より詳細には、本実施形態の板金成形品の製造方法は、まず、パンチ32としてフランジアップ用パンチを用いて、フランジ部を形成し、予成形品を得るフランジアップ工程を備え、次いで、パンチ32としてリストライク用パンチを用いて、予成形品を目標形状の板金成形品にリストライクするリストライク工程を備える。 More specifically, the method for manufacturing a sheet metal molded product of the present embodiment first includes a flange-up step of forming a flange portion by using a flange-up punch as the punch 32 to obtain a preformed product, and then punching. As 32, a rest-like step is provided in which a pre-molded product is rest-liked into a sheet metal molded product having a target shape by using a rest-like punch.

プレス成形工程が2工程以上で構成されるのは、一般的である。しかしながら、通常、フランジ部を形成する工具(ダイ及びパンチ)、リストライクを行う工具は、製品である板金成形品と同じ形状であり、同一の曲率を有している。 It is common that the press forming process is composed of two or more steps. However, usually, the tool for forming the flange portion (die and punch) and the tool for performing retreating have the same shape as the sheet metal molded product which is a product, and have the same curvature.

これに対して、本実施形態の板金成形品の製造方法で用いる工具(ダイ、パンチの一方又は両方)は、フランジアップ用工具とリストライク用工具で形状が異なる。具体的には、フランジアップ用工具の凸状部はリストライク用工具の曲率部より大きな曲率の大曲率部を有する。このような形状とすることにより、フランジ部の該曲率部が接触する部位での引張変形量が増加する。 On the other hand, the tools (one or both of the die and the punch) used in the method for manufacturing the sheet metal molded product of the present embodiment have different shapes between the flange-up tool and the wrist-like tool. Specifically, the convex portion of the flange-up tool has a large curvature portion having a curvature larger than the curvature portion of the wrist-like tool. With such a shape, the amount of tensile deformation at the portion where the curved portion of the flange portion comes into contact increases.

これにより、フランジアップ工程におけるフランジ部の変形領域がフランジの周方向に拡大し、周方向における引張変形が広い範囲で行われるので、ひずみが分散する。その結果、ひずみの最大値が低減する。言い換えれば、局所的なひずみの集中を避けることができる。フランジの湾曲部頂点付近で割れが生じるのは、その領域にひずみが集中し、局所的に変形が大きくなるためである。本実施形態によれば、フランジ部に導入されるひずみ量の最大値が低減し、フランジの湾曲部頂点付近での割れの発生が抑制される。 As a result, the deformation region of the flange portion in the flange-up process expands in the circumferential direction of the flange, and the tensile deformation in the circumferential direction is performed in a wide range, so that the strain is dispersed. As a result, the maximum strain value is reduced. In other words, local strain concentration can be avoided. The cracks occur near the apex of the curved portion of the flange because the strain is concentrated in that region and the deformation is locally increased. According to this embodiment, the maximum value of the amount of strain introduced into the flange portion is reduced, and the occurrence of cracks near the apex of the curved portion of the flange is suppressed.

図4は、本実施形態の板金成形品の製造方法におけるフランジ周方向のひずみ分布と、従来技術による板金成形品の製造方法におけるフランジ周方向のひずみ分布を比較した図である。本実施形態によれば、図4に示すように、フランジ周方向に変形領域が拡大し、ひずみが分散して局所的に集中することがなくなり、ひずみの最大値が低下する。 FIG. 4 is a diagram comparing the strain distribution in the flange circumferential direction in the method for manufacturing a sheet metal molded product of the present embodiment with the strain distribution in the flange circumferential direction in the method for manufacturing a sheet metal molded product according to the prior art. According to the present embodiment, as shown in FIG. 4, the deformation region expands in the circumferential direction of the flange, the strain is not dispersed and locally concentrated, and the maximum value of the strain is lowered.

図5はフランジアップ用工具の形状を説明する図である。図5の50はリストライク用工具の凸状部の平面視である。リストライク用工具の凸状部の曲率半径をRとする。51はフランジアップ用工具の凸状部の比較例であり、凸状部の線長がリストライク用工具の凸状部の線長と同じになっている。フランジアップ用工具の凸状部51の曲率半径をrとする。このとき、50の曲率の中心から50へ引いた垂線と、51の曲率の中心から上記垂線と平行に引いた線の距離をLと定義する。 FIG. 5 is a diagram illustrating the shape of the flange-up tool. 50 in FIG. 5 is a plan view of the convex portion of the wrist-like tool. Let R be the radius of curvature of the convex portion of the wrist-like tool. Reference numeral 51 denotes a comparative example of the convex portion of the flange-up tool, in which the line length of the convex portion is the same as the line length of the convex portion of the wrist-like tool. Let r be the radius of curvature of the convex portion 51 of the flange-up tool. At this time, the distance between the perpendicular line drawn from the center of the curvature of 50 to 50 and the line drawn parallel to the perpendicular line from the center of the curvature of 51 is defined as L.

52はフランジアップ用工具の凸状部の発明例である。このとき、50の曲率の中心から50へ引いた垂線に平行に、52の曲率の中心から平行に引いた直線と、51の曲率の中心から上記垂線と平行に引いた線の距離を、上記のLを基準としてα×Lと定義する。53はフランジアップ用工具の凸状部の比較例であり、凸状部の線長がリストライク用工具の凸状部の線長よりも長くなっている。この形状についても同様にα×Lを定義する。ここで、αは、リストライク用工具の凸状部の先端への方向を+、凸状部から遠ざかる方向を−とする。 52 is an example of the invention of the convex portion of the flange-up tool. At this time, the distance between the straight line drawn parallel to the perpendicular line drawn from the center of the curvature of 50 to 50 and parallel to the center of the curvature of 52 and the line drawn parallel to the perpendicular line from the center of the curvature of 51 is set as described above. It is defined as α × L with reference to L of. Reference numeral 53 denotes a comparative example of the convex portion of the flange-up tool, in which the line length of the convex portion is longer than the line length of the convex portion of the wrist-like tool. Α × L is similarly defined for this shape. Here, α is defined as + in the direction toward the tip of the convex portion of the wrist-like tool and − in the direction away from the convex portion.

図6(a)、(b)は、引張強さ780MPaの鋼板を用いて、曲率半径Rのフランジを成形するときの、フランジアップ用パンチの上記r、αと、最大主ひずみの低減効果(曲率半径Rの曲率部のみを有するパンチとの比較)を示す図である。曲率半径Rは、(a)はR=15mm、(b)はR=30mmである。鋼板の板厚は(a)、(b)とも1.8mmである。どちらの例でも広い範囲でひずみの低減が確認できた。 6 (a) and 6 (b) show the above r and α of the flange-up punch and the effect of reducing the maximum principal strain when forming a flange having a radius of curvature R using a steel plate having a tensile strength of 780 MPa. It is a figure which shows the comparison with the punch which has only the curvature part of the radius of curvature R). The radius of curvature R is R = 15 mm in (a) and R = 30 mm in (b). The thickness of the steel plate is 1.8 mm for both (a) and (b). In both cases, the reduction of strain was confirmed in a wide range.

このようなひずみの分散の効果はフランジアップ工程における変形領域を、製品形状比べて拡大することにより得られるので、その効果が得られれば、上記r、αは特に限定されるものではないが、−0.23R+1.7≦α≦−0.17R+2.3、0.57R≦r≦ 0.77Rとするのが好ましい。 Since the effect of such strain dispersion can be obtained by expanding the deformation region in the flange-up process as compared with the product shape, the above r and α are not particularly limited as long as the effect is obtained. It is preferable that −0.23R + 1.7 ≦ α ≦ −0.17R + 2.3 and 0.57R ≦ r ≦ 0.77R.

以上のように、ひずみを分散することにより、特定箇所におけるひずみの集中を低減することができる。したがって、本実施形態の板金成形品の製造方法によれば、フランジの湾曲部頂点付近において割れが生じることが抑制された、伸びフランジを有する板金成形品を得ることができる。 As described above, by dispersing the strain, the concentration of the strain at a specific location can be reduced. Therefore, according to the method for manufacturing a sheet metal molded product of the present embodiment, it is possible to obtain a sheet metal molded product having an elongated flange in which cracks are suppressed from occurring near the apex of the curved portion of the flange.

また、前述のとおり、一般的に、プレス成形工程は2工程以上で構成されている。したがって、本発明は、従来のプレス成形装置を工具形状の変更のみで適用することができる。そして、本実施形態は、フランジアップ工程とリストライク工程で、工具の凸状部の形状を変えることにより実施できるので、金型サイズ、工具以外の金型構成部品の仕様、製品形状の変更は必要なく、従来のプレス成形装置を使用することができる。 Further, as described above, the press molding process is generally composed of two or more steps. Therefore, the present invention can be applied to the conventional press molding apparatus only by changing the tool shape. Since this embodiment can be implemented by changing the shape of the convex portion of the tool in the flange-up process and the rest-like process, the mold size, the specifications of the mold components other than the tool, and the product shape can be changed. Conventional press forming equipment can be used without the need for it.

21 フランジアップ用工具の凸状部
22 大曲率部
23 直線部(小曲率部)
26 リストライク用工具の凸状部
31 ダイ
32 パンチ
33 ブランクホルダー
34 ブランク
50 リストライク用工具の凸状部
51 フランジアップ用工具の凸状部(比較例)
52 フランジアップ用工具の凸状部(発明例)
53 フランジアップ用工具の凸状部(比較例)
21 Convex part of flange-up tool 22 Large curvature part 23 Straight part (small curvature part)
26 Convex part of wrist-like tool 31 Die 32 Punch 33 Blank holder 34 Blank 50 Convex part of wrist-like tool 51 Convex part of flange-up tool (comparative example)
52 Convex portion of flange-up tool (invention example)
53 Convex part of flange-up tool (comparative example)

Claims (6)

外周縁の一部が内方に向かって突出した凹状外周縁部を有する天板部と、前記凹状外周縁部から連続して内方に向かって湾曲するフランジ部とを備えた板金成形品の製造方法であって、
ブランクに前記フランジ部を形成し予成形品を得るフランジアップ工程と、
前記予成形品を目標形状の板金成形品にリストライクするリストライク工程を備え、
平面視で、前記予成形品の前記フランジ部は、前記板金成形品の前記フランジ部を構成する曲率部の曲率よりも大きい曲率を有する2つの大曲率部と、これらに挟まれる前記板金成形品の前記フランジ部を構成する曲率部の曲率よりも小さい曲率を有する小曲率部で構成され、
前記予成形品の前記フランジ部は、平面視における線長が、前記板金成形品の前記フランジ部の平面視における線長と比較して短い
ことを特徴とする板金成形品の製造方法。
A sheet metal molded product having a top plate portion having a concave outer peripheral edge portion in which a part of the outer peripheral edge protrudes inward, and a flange portion continuously curved inward from the concave outer peripheral edge portion. It ’s a manufacturing method,
A flange-up process in which the flange portion is formed on a blank to obtain a preformed product,
It is provided with a rest-like process for rest-like the pre-molded product into a sheet metal molded product having a target shape.
In a plan view, the flange portion of the preformed product has two large curvature portions having a curvature larger than the curvature of the curvature portion constituting the flange portion of the sheet metal molded product, and the sheet metal molded product sandwiched between them. It is composed of a small curvature portion having a curvature smaller than the curvature of the curvature portion constituting the flange portion of the above.
A method for manufacturing a sheet metal molded product, wherein the flange portion of the preformed product has a line length in a plan view shorter than that of the flange portion of the sheet metal molded product in a plan view.
前記小曲率部は、平面視で直線部である
ことを特徴とする請求項1に記載の板金成形品の製造方法。
The method for manufacturing a sheet metal molded product according to claim 1, wherein the small curvature portion is a straight portion in a plan view.
外周縁の一部が内方に向かって突出した凹状外周縁部を有する天板部と、前記凹状外周縁部から連続して内方に向かって湾曲するフランジ部とを備えた板金成形品を製造する板金成形品の製造装置であって、
前記凹状外周縁部に対応する凸状部を有するフランジアップ用工具、前記凹状外周縁部に対応する凸状部を有するリストライク用工具を備え、
前記フランジアップ用工具の凸状部は、平面視で、前記リストライク用工具の凸状部を構成する曲率部の曲率よりも大きい曲率を有する2つの大曲率部と、これらに挟まれる前記板金成形品の前記リストライク用工具の凸状部を構成する曲率部の曲率よりも小さい曲率を有する小曲率部で構成され、
前記フランジアップ用工具の凸状部は、平面視における線長が、前記リストライク用工具の凸状部の平面視における線長と比較して短い
ことを特徴とする板金成形品の製造装置。
A sheet metal molded product having a top plate portion having a concave outer peripheral edge portion in which a part of the outer peripheral edge protrudes inward, and a flange portion continuously curved inward from the concave outer peripheral edge portion. It is a manufacturing equipment for sheet metal molded products to be manufactured.
A flange-up tool having a convex portion corresponding to the concave outer peripheral edge portion and a rest-like tool having a convex portion corresponding to the concave outer peripheral edge portion are provided.
The convex portion of the flange-up tool has two large curvature portions having a curvature larger than the curvature of the curvature portion constituting the convex portion of the restorative tool in a plan view, and the sheet metal sandwiched between them. It is composed of a small curvature portion having a curvature smaller than the curvature of the curvature portion constituting the convex portion of the rest-like tool of the molded product.
The convex portion of the flange-up tool is a sheet metal molded product manufacturing apparatus characterized in that the line length in a plan view is shorter than the line length in a plan view of the convex portion of the restlike tool.
前記小曲率部は、平面視で直線であることを特徴とする請求項3に記載の板金成形品の製造装置。 The apparatus for manufacturing a sheet metal molded product according to claim 3, wherein the small curvature portion is a straight line in a plan view. 請求項3に記載の板金成形品の製造装置に用いるフランジアップ用工具であって、
板金成形品にフランジを形成するための凸状部を備え、
前記凸状部は、平面視で、2つの大曲率部、及び前記2つの大曲率部に挟まれる、前記大曲率部よりも曲率が小さい小曲率部を有する
ことを特徴とするフランジアップ用工具。
A flange-up tool used in the sheet metal molded product manufacturing apparatus according to claim 3.
A convex part for forming a flange on a sheet metal molded product is provided.
The flange-up tool is characterized in that the convex portion has two large curvature portions and a small curvature portion having a curvature smaller than that of the large curvature portion, which is sandwiched between the two large curvature portions in a plan view. ..
前記小曲率部は、平面視で直線であることを特徴とする請求項5に記載のフランジアップ用工具。 The flange-up tool according to claim 5, wherein the small curvature portion is a straight line in a plan view.
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