JP5360995B2 - Overhang mold and overhang molding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the quality of a formed part, to increase energy efficiency in forming an overhang and to raise the yield of materials in forming the overhang. <P>SOLUTION: By making both edge parts of a sheet-metal workpiece W slide in the separating direction each other and in the same direction as the direction M in the extended surface of a forming surface 21 of a punch 20 or in an inclined direction to the side of the punch 20 than that, it is prevented that a sharp bent part and a longitudinal wall part are formed so as to hinder the extension of the formed part W1 on the sheet-metal workpiece W. Thus, because the formed part W1 is satisfactorily extendable, the improvement of quality is attained and energy is spendable efficiently to extend the formed part. Further, because the longitudinal wall part is not formed, the yield is raised. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to an overhang mold and an overhang molding method.

  Overhang molding is a molding method in which a sheet metal workpiece is stretched and pressed into a mold molding surface and plastically deformed to form a predetermined shape. It is applied to the molding of panel parts having

  For example, Patent Document 1 discloses an overhang mold as shown in FIGS. 11 and 12 as a conventional technique. In this overhanging mold, both edge portions W2 of the sheet metal workpiece W are held by the blank holders 101 and 102 (see FIG. 11), and in this state, the blank holders 101 and 102 are lowered to press the sheet metal workpiece W against the punch 103. Thus, the forming part W1 of the sheet metal workpiece W is formed into a predetermined shape (see FIG. 12). In this case, as shown in FIG. 13, as the blank holders 101 and 102 are lowered, a bent portion P is formed at the end of the forming portion W1 formed by the forming surface 103a of the punch 103 in the sheet metal workpiece W. The vertical wall portion W3 is formed through the bent portion P. That is, by lowering the blank holders 101 and 102, the molding is performed by applying a tensile force to the molding part W1 while extending the vertical wall part W3 up and down. In addition, the name and code | symbol different from patent document 1 are attached | subjected to each site | part of FIGS.

Japanese Patent Laid-Open No. 9-15224

  When performing overhang molding with the above mold, as shown in FIG. 13, as the blank holders 101 and 102 descend and the molding proceeds, the vertical wall portion W3 approaches the vertical direction. The angle θ ′ between the extending surface direction M ′ of 103a and the extending direction S ′ of the vertical wall portion W3 is increased, and a sharply bent portion P close to a right angle is formed between the vertical wall portion W3 and the molded portion W1. Is done. Since the sheet metal workpiece W is wound around the bent portion P and the elongation of the molding portion W1 is hindered, it is difficult to sufficiently stretch the molding portion W1, and the quality of the molding portion W1 may be deteriorated. Further, when the bending portion P hinders the elongation of the molding portion W1, the vertical wall portion W3 is greatly stretched (for example, about 10 to 15%) with respect to the elongation (for example, about 2-3%) of the molding portion W1. However, since the vertical wall portion W3 is usually separated from the molded portion W1 (design surface) and discarded, or is bent to the back side of the molded portion W1, it is not necessary to greatly stretch the vertical wall portion W3. Is wasting energy. Furthermore, it is necessary to design the shape of the vertical wall portion W3 of the sheet metal work W so that the vertical wall portion W3 can be prevented from being broken by stretching and the amount of elongation of the forming portion W1 can be secured. Incurs a decline.

  Patent Document 1 describes an invention in which a sheet metal workpiece is pulled in a horizontal direction to apply a pretension, thereby increasing the amount of stretch of the forming portion and reducing the surplus portion (vertical wall portion). However, this pre-tension is to stretch the sheet metal work in the horizontal direction prior to forming the design surface, and the design surface of the sheet metal work is formed by lowering the blank holder and pressing the sheet metal work against the punch. Is called. Therefore, it does not change that a sharp bent part or a vertical wall part is formed in the sheet metal work, and it is possible to solve problems such as deterioration of the quality of the molding part, reduction of energy efficiency at the time of molding, or reduction of yield. I can not say.

  The problem to be solved by the present invention is to improve the quality of the molded part in the stretch molding, to increase the energy efficiency during molding, and to further increase the yield of the material.

  In order to solve the above problems, the present invention provides a molding surface in a state in which a punch having a molding surface for molding a design surface of a component and a sheet metal work as a base material of the component are placed along the molding surface. An overhang molding die provided with a pair of blank holders for holding both end edges of the sheet metal work protruding from the pair of blank holders in directions away from each other and an extension surface direction of the molding surface A slide mechanism is provided that slides in the same direction or a direction inclined more toward the punch side than that.

  Further, the present invention is a step of placing the sheet metal workpiece along the molding surface of the punch for molding the design surface of the component, and both edge portions of the sheet metal workpiece protruding from the molding surface, in directions away from each other, and A step of forming a design surface by pressing a sheet metal work against the forming surface by pulling along a direction that is the same as the extending surface direction of the forming surface or inclined more toward the punch side than that. It can also be attached.

  In the present invention, the pair of blank holders holding the both end edges W2 of the sheet metal work W are not lowered in parallel (see FIGS. 11 and 12), but are slid in directions away from each other, and the both end edges of the sheet metal work , The angle θ between the extending surface direction M of the punch forming surface and the sliding direction S of the sheet metal work is reduced (see FIGS. 5 and 7), and the sharply bent portion P (see FIG. 5 and FIG. 7) is formed. 13) can be avoided. Thereby, the shaping | molding part of a sheet-metal workpiece can be fully extended, and the improvement of quality can be aimed at. Further, since the vertical wall portion W3 (see FIG. 13) through the sharp bent portion is not formed on the sheet metal work, energy for stretching the vertical wall portion is not required, and the tensile energy due to sliding of the blank holder is efficiently formed. Can be spent on stretching. Furthermore, since the vertical wall portion W3 is not formed, the yield can be increased.

  From the viewpoint of not forming a bent portion in the sheet metal workpiece W during the overhang forming, it is ideal that the sheet metal workpiece pulling direction (sliding direction S of the blank holder) matches the extending surface direction M of the punch forming surface. Yes (see FIG. 5). However, it is not always necessary to match both directions, and unless a sharp bent part or vertical wall part that inhibits the elongation of the forming part is formed, the pulling direction of the sheet metal work and the extending surface direction of the forming surface are different. Also good. However, if the sheet metal workpiece pulling direction is inclined to the side away from the punch with respect to the extending surface direction of the molding surface, a part of the molding part (near the edge) of the sheet metal workpiece will not contact the molding surface of the punch. Since there is a risk of forming defects, the pulling direction of the sheet metal work must be the same as the extending surface direction of the forming surface or inclined more toward the punch side than that.

  A blank holder can be comprised by a pair of holder member which clamps a sheet-metal workpiece, for example. When the blank holder is slid, if one holder member slides in the sliding direction with respect to the other holder member, the holding force of the sheet metal work by the blank holder may be hindered. Therefore, if the pair of holder members are engaged with each other in the sliding direction in any direction, relative sliding (positional deviation) in the sliding direction of the pair of holder members can be reliably prevented.

  As described above, according to the present invention, it is possible to improve the quality of a molded part, increase the energy efficiency at the time of molding, and further increase the yield of the material in overhang molding.

It is a top view which shows the outer panel of the door shape | molded from a sheet metal workpiece. It is sectional drawing of an overhang | molding metal mold | die (before shaping | molding start). FIG. 3 is a cross-sectional view of an overhang mold (with both ends of a sheet metal work held). It is sectional drawing of an overhang molding die (at the time of overhang molding). It is an expanded sectional view of an overhang mold. It is sectional drawing of an overhang | molding metal mold | die (at the time of shaping | molding completion). It is an expanded sectional view of the overhang mold in another section. It is a perspective view of the holder member of the blank holder concerning other embodiments. (A) is sectional drawing of the blank holder concerning other embodiment, (b) is sectional drawing in the position where the blank holder differs. It is sectional drawing which shows the reference example of a blank holder. It is sectional drawing of the conventional extending | stretching mold (before shaping | molding start). It is sectional drawing of the conventional extending | stretching shaping | molding die (at the time of shaping | molding completion). It is an expanded sectional view of the conventional overhang mold.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

A component formed by the overhang molding of the present embodiment is a door outer panel D _O (hereinafter referred to as a door outer D _O ) as shown in FIG. In the following description, the state of molding in the XX cross section of FIG. 1 will be described.

  As shown in FIG. 2, the overhang mold according to this embodiment includes a die 10 fixed to a slidable upper mold slide 1, a punch 20 fixed to a bolster 2 on a fixed side, and a sheet metal workpiece W. And blank holders 30 and 40 for holding the edge portion W2 (see FIG. 3). The upper mold slide 1 and the die 10 are slidable in a direction approaching / separating from the punch 20. In this embodiment, the case where the sliding direction of the upper mold | type slide 1 and the die | dye 10 is an up-down direction is shown. For convenience of explanation, a direction orthogonal to the vertical direction (the horizontal direction in the figure) in FIG. 2 is referred to as the width direction.

Die 10, as shown in FIG. 2, Doaauta D and _O of the design surface to gently concave curved surface of the pressing surface 11 along, Doaauta D _O of the design surface on the recess (e.g., recess of the handle portion H, FIG. 1 For example, and an upper slide surface 13 provided on both outer sides in the width direction of the pressing surface 11. The upper slide surface 13 constitutes one element of a slide mechanism for sliding the blank holders 30 and 40, and is inclined upward toward the outer side in the width direction in the illustrated example.

As shown in FIG. 2, the punch 20 presses the sheet metal workpiece W with a gently convex curved molding surface 21 along the design surface of the door outer D _O and the convex portion 12 of the die 10, whereby the door outer D _O is pressed. A recess 22 for forming a recess on the design surface, and a lower slide surface 23 provided on both outer sides in the width direction of the molding surface 21. The lower slide surface 23 constitutes one element of a slide mechanism for sliding the blank holders 30, 40, and is an extension surface direction M of the molding surface 21 of the punch 20 (that is, a tangential direction at the end 21 a of the molding surface 21, 2), and in particular, in the illustrated example, it is inclined downward toward the outside in the width direction so as to be parallel to the extended surface direction M.

  The blank holders 30 and 40 hold the edge of the sheet metal workpiece W, are arranged on both outer sides in the width direction of the molding surface 21 of the punch 20, and are slidable with respect to the die 10 and the punch 20. Hereinafter, although the specific structure of one blank holder 30 is demonstrated, since the structure of the other blank holder 40 is also the same, duplication description is abbreviate | omitted.

  The blank holder 30 includes a pair of upper and lower holder members 31 and 32. The upper holder member 31 is attached to the die 10 via an elastic member 33 such as a spring, and is slidable along the upper slide surface 13 of the die 10. The lower holder member 32 is attached to the punch 20 via an elastic member 34 such as a spring and is slidable along the lower slide surface 23 of the punch 20. The work holding surfaces 31a and 32a of the holder members 31 and 32 are provided horizontally. The work holding surface 31a of the upper holder member 31 is formed with a groove 31a1 extending in its longitudinal direction (a direction orthogonal to the cross section shown in FIG. 2), and the work holding surface 32a of the lower holder member 32 is formed on the work holding surface 32a. A convex portion 32a1 corresponding to the groove 31a1 of the upper holder member 31 and extending in the longitudinal direction is formed. On the contrary, the upper holder member 31 may be provided with a convex portion and the lower holder member 32 may be provided with a groove.

  A stretch forming method using the stretch molding die having the above-described configuration will be described with reference to FIGS.

  First, as shown in FIG. 2, the sheet metal workpiece W is placed on the molding surface 21 of the punch 20 with the die 10 and the punch 20 opened. At this time, the blank holders 30 and 40 are disposed at the most central position, that is, the upper holder members 31 and 41 are disposed adjacent to both outer sides in the width direction of the pressing surface 11 of the die 10 and the lower holder members 31 and 41 are disposed on the lower side. The holder members 32 and 42 are disposed adjacent to both outer sides in the width direction of the molding surface 21 of the punch 20.

  Next, the upper mold slide 1 and the die 10 are lowered, and the upper holder members 31 and 41 push down the edge W2 of the sheet metal workpiece W while lowering the workpiece holding surfaces 31a and 41a of the upper holder members 31 and 41 and the lower side. The edge portions W2 on both sides in the width direction of the sheet metal workpiece W are sandwiched from above and below by the workpiece holding surfaces 32a and 42a of the holder members 32 and 42 on the side (see FIG. 3). At this time, the sheet metal workpiece W is sandwiched between the grooves 31a1 and 41a1 and the convex portions 32a1 and 42a1, thereby preventing the positional deviation of the sheet metal workpiece W with respect to the blank holders 30 and 40 during the subsequent sliding operation.

  When the upper mold slide 1 and the die 10 are further lowered, the blank holders 30 and 40 are slid in a direction parallel to the extended surface direction M of the molding surface 21 and away from each other in the width direction by the slide mechanism. In the present embodiment, the upper slide surface 13 formed on the die 10 and the lower slide surface 23 formed on the punch 20 constitute a slide mechanism. Specifically, as shown in FIG. 4, the upper holder members 31 and 41 are pushed outward in the width direction by the upper slide surface 13 of the die 10, and accordingly, as shown in an enlarged view in FIG. 5, Blank holders 30 and 40 sandwiching the edge W2 of the sheet metal workpiece W slide outward in the width direction along the lower slide surface 23 of the punch 20 (that is, along the extended surface direction M of the molding surface 21). In this way, the sheet metal workpiece W is pressed against the forming surface 21 of the punch 20 while being pulled outward in the width direction, and is plastically deformed, and is formed along the shape of the forming surface 21.

  Thus, by sliding the blank holders 30 and 40 in directions away from each other, the angle between the sliding direction S of the blank holder and the extended surface direction M of the molding surface 21 is reduced, and thereby the sheet metal workpiece W is moved. The angle between the molding part W1 and the end edge part W2 can be made gentle. In particular, when both directions are matched as shown in FIG. 5, the forming part W1 and the end edge part W2 of the sheet metal workpiece W are smoothly continuous, and no bent part is formed between them. Thereby, while being able to transmit efficiently the tensile force by the slide of the blank holders 30 and 40 to the shaping | molding part W1 of the sheet metal workpiece W, the processing quality of the shaping | molding part W1 (design surface) can be improved. Moreover, since the vertical wall part W3 (refer FIG. 13) of the conventional overhang molded product is not formed, a yield can be improved.

  When the upper mold slide 1 and the die 10 are further lowered, as shown in FIG. 6, the sheet metal workpiece W is further stretched outward in the width direction, and the sheet metal workpiece is formed by the pressing surface 11 of the die 10 and the molding surface 21 of the punch 20. The molded part W1 of W is clamped. At the same time, a concave portion is formed on the sheet metal workpiece W by the convex portion 12 of the pressing surface 11 of the die 10 and the concave portion 22 of the molding surface 21 of the punch 20.

Thus, the overhang forming of the sheet metal workpiece W is completed. Thereafter, the upper mold slide 1 and the die 10 are raised to open the mold, and the formed sheet metal work W is taken out. The door outer D _O is completed by trimming the molded sheet metal work W taken out into a predetermined shape.

Incidentally, the sliding direction S of the blank holder 30 is to match the extension plane direction M of the molding surface 21 as shown in FIG. 5 is ideal, parts such as Doaauta D _O is the end of the design surface by cross Since the inclination angles at the edges are different, it is practically impossible to make the sliding direction S of the blank holder 30 coincide with the extended surface direction M of the molding surface 21 in every cross section. Therefore, depending on the cross section, as shown in FIG. 7, the sliding direction S of the plank holders 30 and 40 may be different from the extended surface direction M of the molding surface 21. At this time, the sliding direction S of the blank holders 30 and 40 is in the punch 20 side (lower side in the figure) with respect to the extended surface direction M of the molding surface 21 in order to make the sheet metal workpiece W abut on the molding surface 21 reliably. It is necessary to incline. In this case, a slight bent portion is formed in the sheet metal workpiece W at the end 21a of the molding surface 21, but the sliding direction S of the blank holder 30 is appropriately set according to the extended surface direction M of the molding surface 21, and the bent portion is formed. By adjusting the angle, the molded portion W1 can be sufficiently stretched.

  The present invention is not limited to the above embodiment. Hereinafter, although other embodiment of this invention is described, the same code | symbol is attached | subjected to the location which has the same structure and function as the said embodiment, and description is abbreviate | omitted.

  For example, in order to prevent relative displacement between the pair of holder members 31, 32 and 41, 42 sandwiching the sheet metal workpiece W, the pair of holder members are engaged with each other in a plane in each direction in the sliding direction. You may make it match. Specifically, for example, as shown in FIG. 8, a convex portion 32b and a concave portion 32c are provided at the outer end in the width direction of the work holding surface 32a of the lower holder member 32, and the upper holder member 31 (see FIG. 9). ) Are provided with a recess 31c and a protrusion 31b at the outer end in the width direction of the work holding surface 31a. When the sheet metal workpiece W is sandwiched between these holder members 31, 32, as shown in FIG. 9A, the convex portion 32b of the lower holder member 32 and the concave portion 31c of the upper holder member 31 are fitted, A situation in which the upper holder member 31 is shifted to the outside in the width direction (right side in the figure) with respect to the lower holder member 32 due to both engaging with each other in the sliding direction (the engagement portion is indicated by Q1). Can be prevented. At the same time, as shown in FIG. 9B, the convex portion 31b of the upper holder member 31 and the concave portion 32c of the lower holder member 32 are fitted, and both are engaged with each other in the sliding direction. (The engagement portion is indicated by Q <b> 2) can prevent the upper holder member 31 from shifting to the inner side in the width direction (left side in the figure) with respect to the lower holder member 32. As described above, by causing the pair of holder members 31 and 32 to engage with each other in any direction in the sliding direction, relative sliding (positional deviation) of the holder members 31 and 32 can be reliably prevented. Can do.

  For example, as shown in FIG. 10, a concave portion 31c ′ is provided in the intermediate portion in the width direction of the work holding surface of the upper holder member 31 ′, and the intermediate portion in the width direction of the work holding surface of the lower holder member 32 ′ is protruded. By providing the portion 32b ′ and fitting them together, it is possible to provide the engaging portions Q1 ′ and Q2 ′ that engage with each other in any direction in the sliding direction. However, the convex portion 32b ′ of the lower holder member 32 ′ and the widthwise outer portion 31d ′ of the concave portion 31c ′ of the upper holder member 31 ′ have a certain width direction in order to ensure the strength that can withstand engagement. Therefore, if these are arranged side by side in the width direction, the overall dimension in the width direction of the blank holder 30 'increases. In particular, in the overhang mold of the present invention, the blank holder is slid outward in the width direction, and therefore the width direction dimension of the entire mold tends to be large. Therefore, it is preferable to make the width direction dimension of the blank holder compact. Therefore, as shown in FIGS. 8 and 9, if the protrusions 31 b and 32 b that need to have a thickness in the width direction that can withstand engagement are provided at the same position in the width direction, the width direction dimension of the blank holder 30 can be increased. Can be suppressed.

DESCRIPTION OF SYMBOLS 1 Upper mold | type 2 Bolster 10 Die 20 Punch 21 Forming surface 30 Blank holder 31, 32 Holder member 40 Blank holder 41, 42 Holder member M Forming surface extension surface direction S Blank holder sliding direction W Sheet metal work W1 Forming part W2 End Edge

Claims (3)

Hold both edge portions of the sheet metal work protruding from the molding surface with the punch having the molding surface for molding the design surface of the part and the sheet metal work as the base material of the part along the molding surface. An overhang mold having a pair of blank holders,
An overhanging metal mold provided with a slide mechanism that slides a pair of blank holders in directions away from each other and in the same direction as the extended surface direction of the molding surface or inclines toward the punch side. Type.   2. The overhanging metal mold according to claim 1, wherein the blank holder is composed of a pair of holder members that sandwich the edge portion of the sheet metal workpiece, and the pair of holder members are engaged with each other in a plane in each direction in the sliding direction. Type.   The step of aligning the sheet metal workpiece with the molding surface of the punch for molding the design surface of the part, and the both end edges of the sheet metal workpiece protruding from the molding surface in directions away from each other, and an extended surface of the molding surface A step of forming a design surface by pressing a sheet metal work against the forming surface by pulling along a direction that is the same as the direction or inclined toward the punch side.

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