JP2005186156A - Method and device for press molding of metal sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a press molding method and device which can efficiently form a plurality of projections on even a metal sheet which is low in ductility and thin in thickness. <P>SOLUTION: In a press molding method of forming a plurality of the projections 40 on the metal sheet 10 by use of a die and a punch, either the die or the punch is a female mold 2 having a plurality of concaves 21 of a desired shape, and the other is a male mold 1 having a plurality of convexes 11 of which the tip diameter is smaller than the minimum representative dimension of the concaves 21. The metal sheet 10 is pressed by the die and the punch so that the plurality of the concaves 21 and the plurality of the convexes 11 are fitted each other. At least one of the female mold 2 and the male mold 1 is moved so that the convexes 11 rotate and move along the inner circumferences of the side walls of the concaves 21 for ironing the walls of the projections 40 being formed on the metal sheet 10. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a metal plate press forming method and apparatus, and more particularly, to a metal plate press forming method and apparatus suitable for embossing for forming a plurality of protrusions on a metal plate.

In many cases, press forming is used to process a metal plate into a member having a desired shape. Further processing is often performed on the member after press molding. Press forming is most frequently used as a method for forming a metal plate because it has higher productivity and higher yield than other methods. There are two types of press molding, one by overhanging and the other by drawing. For example, as shown in FIG. 9, a metal plate is formed into a protrusion shape by a combination of a concave die, a convex punch, and a wrinkle presser. At this time, it is a forming method by overhanging that the metal plate is strongly pressed by wrinkle pressing so that the outer edge portion of the metal plate is not drawn into the concave mold. In this forming method by overhang, a material metal plate such as ferritic stainless steel or aluminum having a low ductility often breaks or is pierced by forming. In this regard, according to the forming method by drawing, the outer edge portion of the metal plate is drawn in the center direction to become the vertical wall portion of the protrusion, so that the material metal such as ferritic stainless steel or aluminum that has relatively small ductility and is easy to break. Even plates can be formed into deep protrusions. However, as shown in FIG. 10, in the case of a so-called embossed shape having a plurality of protrusions, even if trying to form in the same manner, the action of the material metal plate flowing from the surroundings competes with each other as described above. However, the outer edge cannot be drawn in, and it is mainly stretch-molded depending on the ductility of the material metal plate. Here, since the stretch formability is almost determined by the ductility of the material metal plate, a material having a small ductility such as ferritic stainless steel or aluminum cannot be formed into a deep protrusion shape. As an improvement measure for this, an overhang portion is formed by the first press die in the first step, and an overhang portion is formed from the peripheral portion of the overhang portion formed in the first step by the second press die in the next second step. A method is disclosed in which the inner part close to the center of the part is pressed to complete the formation of the protrusion (see, for example, Patent Document 1).
JP 2000-317531 A (FIG. 5 etc.)

However, even in the above method, when pressing the flat portion of the projection top in the second step, the thinner the material metal plate, the higher the pressing load, and the less the effect of swept around the material metal plate, Eventually, the material metal plate is not sufficient, and a failure such as breakage is likely to occur, and it is still difficult to form a deep protrusion.
The present invention has been made to solve the above-described problems. A press forming method, particularly a metal plate, can efficiently form a plurality of protrusions even when a metal plate having a small ductility and a thin plate thickness is used. An object of the present invention is to propose a molding method and a molding apparatus for efficiently performing embossing to form a plurality of protrusions.

  The processing method of the present invention is a metal plate press forming method in which a die and a punch are used to form a plurality of protrusions on a metal plate, and one of the die and the punch has a plurality of concave portions having a desired shape. A concave mold is used, and on the other hand, a convex mold having a plurality of convex portions whose tip diameter is smaller than the minimum representative dimension of the concave portion is used, and the plurality of concave portions and the plurality of the metal plate are formed by the die and the punch. The metal is pressed so that the convex part of the metal part is fitted, and at least one of the concave part and the convex part is moved so that the convex part moves around the inner periphery of the side wall of the concave part. The wall portion of the protrusion being formed on the plate is ironed.

  Further, the movement of the convex shape or the concave shape is to change the shift amount of the convex portion from the center of the concave portion and to make the convex portion circulate a plurality of times along the inner periphery of the side wall of the concave portion. And

  Further, the movement of the convex shape or the concave shape includes shifting the convex portion in a spiral shape from the central portion of the concave portion toward the side wall.

  The processing apparatus of the present invention is a press forming apparatus that forms a plurality of protrusions on a metal plate using a die and a punch, and one of the die and the punch has a concave shape having a plurality of recesses of a desired shape. And the other is a convex shape having a plurality of convex portions whose tip diameter is smaller than the minimum representative dimension of the concave portion, and at least one of the concave shape and the convex shape is advanced and retracted toward the other. The at least one of the concave mold and the convex mold is movably formed so that the convex section can relatively move around the inner periphery of the side wall of the concave section.

  Further, in the above processing apparatus, the tip of the convex convex portion is detachable.

  According to the present invention, a plurality of protrusions can be simultaneously formed on a metal plate having a small ductility and a thin plate thickness. In particular, deep embossing, which cannot be processed by ordinary press molding, can be processed into a metal plate, and an embossed plate used for applications that require design properties such as electrical products can be efficiently manufactured.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following drawings, the same reference numerals are used for the same components or equivalents. Fig.1 (a) is a cross-sectional schematic diagram which shows an example of the structure of the type | mold which implements the press molding process method of this invention. In the press molding of the present invention, a convex mold 1 as a punch and a concave mold 2 as a die used in combination with the convex mold 1 are used. The concave mold 2 is formed with a plurality of concave portions 21 having a desired shape corresponding to the shape of the projection to be formed by processing the material metal plate 10. On the other hand, the convex mold 1 is formed with a plurality of convex portions 11 that fit into the concave portions 21 of the concave mold 2. As shown in FIG. 1B, the outer diameter de of a portion that is substantially used for forming when the metal plate 10 is pushed into the recess 21 as shown in FIG. In addition, it is desired that the metal plate 10 be configured to be smaller than the inner diameter D of the projection to be formed. In order to achieve the object, the tip diameter d of the convex portion 11 is made smaller than the minimum representative dimension of the concave portion 21. The maximum diameter Dmax of the cross section of the convex portion 11 may be made smaller than the minimum representative dimension of the concave portion 21. The minimum representative dimension of the recess 21 is the diameter a when the cross-sectional shape of the mouth of the recess 21 is circular as shown in FIG. 1D, and the short diameter when the cross-sectional shape is elliptic as shown in FIG. b, in the case of a rounded rectangle as shown in FIG.
Reference numeral 3 in the figure denotes a holder that holds the metal plate 10 while being pressed between the concave mold 2 and has a diameter slightly larger than the maximum diameter Dmax of the convex portion 11 so that the convex portion 11 can pass therethrough. A plurality of through-holes 31 are provided. A plurality of the protrusions 11, the recesses 21, and the through holes 31 are provided, and a plurality of protrusions are simultaneously formed on the metal plate 10. In the following process diagrams, the forming situation of one protrusion is shown. Next, the press molding method of the present invention using these convex mold 1, concave mold 2 and holder 3 will be described.

Embodiment 1
FIG. 2 is a process diagram for explaining the first embodiment of the method of the present invention. In this method, first, the material metal plate 10 is fixed between the concave mold 2 and the holder 3, and the convex mold 1 is positioned so that the convex section 11 is positioned at a position corresponding to the concave section 21 of the concave mold 2 and the through hole 31 of the holder 3. Is arranged (FIG. 2A). In this state, the central axis 12 of the convex part 11 and the central axis 22 of the concave part 21 coincide. Subsequently, the convex portion 11 of the convex mold 1 shifts the distance r1 with respect to the central axis 22 of the concave section 21 of the concave mold 2, revolves (rotates) around the central axis 22 while maintaining this distance, and descends. A part of the metal plate 10 is contacted (FIG. 2B). Furthermore, the convex portion 11 of the convex mold 1 moves along the periphery of the side wall of the concave portion 21 of the concave mold 2, and revolves (circulates) around the central axis 22 to finish one round of machining (FIG. 2 (c)). At this time, ironing is performed between the convex part 11 and the concave part 21, and the thickness of the metal plate 10, especially the thickness of the vertical wall part of the protrusion 40 is reduced.

  Next, the convex portion 11 of the convex mold 1 is shifted to a position where the distance r2 (in this case, r2 ≦ r1) with respect to the central axis 22 of the concave portion 21 of the concave mold 2 and revolves around the central axis 22 ( It goes down to the final height while going around (FIG. 2 (d)). Then, the convex portion 11 of the convex mold 1 continues to move along the periphery of the side wall of the concave portion 21 of the concave mold 2, and revolves (circulates) around the central axis 22 to complete one round of machining (FIG. 2 (e)). Also by this, the ironing process in which the thickness of the metal plate 10 is reduced between the convex part 11 and the concave part 21 is performed. As a result, a protrusion 40 having a predetermined shape is formed on the metal plate 10.

  Note that the shift amount r2 of the second convex portion 11 does not necessarily have a relationship of r2 ≦ r1, and may be determined according to the shape of the projection 40 to be molded. For example, if the projection 40 is cylindrical, r2 ≧ r1 is more effective for ironing. Further, the number of turns along the periphery of the side wall of the concave portion 21 of the convex portion 11 may be appropriately determined according to the molding state of the protrusion 40, and may be one time, or may be twice or more.

  According to such a method, since the projection 40 is formed not by drawing but mainly by ironing, even if it is performed simultaneously at a plurality of locations, the inflow of the material metal plate 10 competes with each other. Such a problem is substantially eliminated, and even if the metal plate 10 has a small ductility and a thin plate thickness, a plurality of protrusions 40 can be formed simultaneously.

Embodiment 2
FIG. 3 is a process diagram for explaining a second embodiment of the method of the present invention. Also in this method, first, the material metal plate 10 is fixed between the concave mold 2 and the holder 3, and the convex part 11 is positioned so as to be positioned at a position corresponding to the concave part 21 of the concave mold 2 and the through hole 31 of the holder 3. A mold 1 is arranged (FIG. 3A). In this state, the central axes 12 and 22 of the convex portion 11 and the concave portion 21 coincide with each other. Subsequently, the convex portion 11 of the convex mold 1 is lowered to the final height, and the metal plate 10 is pushed down into a bowl shape to perform overhanging molding (FIG. 3B). Next, after the convex portion 11 of the convex mold 1 is spirally shifted in the direction of the side wall of the concave portion 21, the convex portion 11 is moved along the periphery of the side wall of the concave portion 21, and the vertical wall portion of the projection 40 is ironed. To reduce the thickness (FIG. 3C). Here, the convex part 11 is recirculated along the periphery of the side wall of the concave part 21, and the vertical wall part is further thinned to form a protrusion having a predetermined shape (FIG. 3D).

  By such a method, since the projection 40 is formed not by drawing but by overhang forming and ironing, even if it is performed at a plurality of locations at the same time, the inflow of the material metal plate 10 competes with each other. Such a problem is substantially eliminated, and even if the metal plate 10 has a small ductility and a thin plate thickness, a large number of protrusions 40 can be simultaneously formed.

  In the first and second embodiments, for convenience of explanation, the convex portion 11 moves with respect to the concave portion 21, that is, the convex die 1 moves with respect to the concave die 2. However, the relationship between the two is as follows. It is a relative thing, and it is good also as a structure which the recessed part 21 moves with respect to the convex part 11, ie, the structure in which the concave mold 2 moves with respect to the convex mold 1, or a structure in which both move.

Embodiment 3
FIG. 4 is a block diagram of a press working apparatus suitable for carrying out the press forming method of the present invention. In FIG. 4, 51 and 52 are housings constituting the outer shell of the processing apparatus, and 53 is a pillar constituting a part of the housing. Reference numeral 54 denotes a hydraulic cylinder that moves one of the convex mold 1 and the concave mold 2 forward and backward (in this case, up and down), and 55 denotes an arbitrary direction in a plane that is two-dimensionally (here, in a horizontal plane). This is an XY table that can be exercised. Furthermore, 61 is a fixture 61 that sandwiches and fixes the material metal plate 10 between one of the convex mold 1 and the concave mold 2 (in the case of the concave mold 2). In order to perform machining efficiently using this machining apparatus, it is desirable that the position control of the hydraulic cylinder 54 and the XY table 55 be NC control.

  In addition, for example, a hydraulic cylinder and an XY table are integrally combined to form a three-axis stage that can move in any direction in the XYZ-axis direction (in a three-dimensional space). It is possible to implement the press molding method of the present invention even in a processing apparatus in which one mold (for example, convex mold 1) is disposed and the other mold (for example, concave mold 2) is completely fixed. Even when one mold is arranged on the three-axis stage, the other mold may be movable in at least one direction of the XYZ axes.

  Furthermore, if the portion directly contacting the metal plate 10 at the tip of the convex 11 of the convex mold 1 is detachable, it can be easily replaced when the tip is worn. For example, as shown in FIG. 5, a ring-shaped protrusion 112 is formed on the outer periphery of the tip portion 111 of the convex portion 11, and a corresponding groove 114 is formed in the replacement tip piece 113, so that the ring-shaped protrusion 112 is formed. And a method of attaching and detaching the replacement tip piece 113 to and from the tip portion 111 by using the fitting between the tip and the groove 114 and the elastic action of the replacement tip piece 113. Of course, the present invention is not limited to this method. In short, any method may be used as long as it can prevent the tip piece 113 from falling off during the ironing process.

  FIG. 6 shows the shape and dimensions of a member formed by the method of the present invention using the above processing apparatus. FIG. 6A is a perspective view showing the entire member, and FIG. 6B is a cross-sectional view showing one of the formed protrusions 40. The metal plate 10 used here is SUS430, which is a material having an elongation value of 28% and a low ductility, but can be processed without causing breakage or the like in the vertical wall portion of the protrusion 40. In addition, this member was manufacturable by either said 1st and 2nd embodiment.

  For comparison, the same member as that shown in FIG. 6 was formed by a conventional press forming method as shown in FIG. In this case, the clearance between the die and the punch is set to be the same as the thickness of the base plate (metal plate) at the bottom dead center, and is overhang forming. In the molding by this method using the same material (SUS430) as that of the example of the present invention, as shown in FIGS. 8 (a) and 8 (b), the vertical wall portion of the protrusion was almost broken, resulting in molding failure. This is because a metal plate having an elongation of about 28% is formed to be stretched by 50% or more, which is theoretically impossible. On the other hand, since the method of the present invention uses the effect of expanding the base plate by reducing the thickness by ironing, it is possible to form a larger strain.

  In the above embodiment, the press molding method of the present invention has been described by giving an example of forming a plurality of frustoconical protrusions. However, the press molding method of the present invention has a cylindrical shape, a cross-sectional elliptical shape, and a cross-sectional angle. It can be applied to form a protrusion having an arbitrary shape such as a round rectangular shape. In that case, a concave mold having a plurality of concave portions of a desired shape corresponding to each of those shapes is used, and the corresponding convex mold has a tip diameter of the convex portion smaller than the minimum representative dimension of the corresponding concave concave portion. The thing which has multiple is used. Furthermore, for the ironing process peculiar to the present invention, the convex convex portion is moved along the inner wall of the concave concave portion, or the concave concave portion is moved with respect to the convex convex portion. The convex protrusion is moved along the inner periphery of the side wall of the concave recess, or both. At this time, the convex convex portion may be rotated a plurality of times along the inner periphery of the side wall of the concave recess according to the molding condition of the vertical wall of the projection to be formed. Further, the convex mold may change the shift amount of the convex portion from the center of the concave portion and move the convex portion so as to circulate a plurality of times along the inner periphery of the side wall of the concave portion. Note that the convex movement may include a spiral shift of the convex portion toward the side wall of the concave portion.

  The press molding method and apparatus of the present invention can efficiently form a plurality of protrusions on a thin metal plate having a small ductility, so that it can be used for manufacturing members used in automobiles, various machine products and electrical products. Widely available. In particular, it is suitable for producing an embossed plate used for applications requiring design properties and a processed product using the embossed plate.

The schematic diagram which shows the example of embodiment of the press molding process of this invention. Process drawing explaining 1st Embodiment of the press molding method of this invention. Process drawing explaining 2nd Embodiment of the press molding method of this invention. The block diagram of the press work apparatus suitable for implementing the press molding process method of this invention. The cross-section figure which shows an example of the convex-shaped convex part front-end | tip part used for the press molding method of this invention. Explanatory drawing which shows an example of the member which can be processed with the press molding processing method of this invention. The process drawing of the press molding by the conventional method used for the comparison with the press molding processing method of this invention. The figure for demonstrating the shaping | molding defect by a conventional method. The figure for demonstrating drawing. The figure for demonstrating the problem of a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Convex type (punch), 2 ... Concave type (die), 3 ... Holder, 10 ... Metal plate (material), 11 ... Convex convex part, 12 ... Center axis of convex part, 21 ... Concave concave part, 22 ... center axis of recess, 40 ... projection, 51, 52 ... housing, 53 ... housing column, 54 ... hydraulic cylinder, 55 ... XY table, 61 ... fixture, 111 ... tip of projection, 112 ... ring projection 113 ... Replacement tip piece, 114 ... Groove.

Claims (5)

In a metal plate press forming method of forming a plurality of protrusions on a metal plate using a die and a punch,
A concave mold having a plurality of concave portions of a desired shape is used for one of the die and the punch,
On the other hand, using a convex mold having a plurality of convex portions whose tip diameter is smaller than the minimum representative dimension of the concave portion,
While pressing the metal plate so that the plurality of recesses and the plurality of projections fit with the die and the punch,
The wall portion of the protrusion being formed on the metal plate by moving at least one of the concave shape and the convex shape so that the convex portion moves relatively along the inner periphery of the side wall of the concave portion. Ironing,
A press forming method for a metal plate.   The movement of the convex shape or the concave shape changes the shift amount of the convex portion from the center of the concave portion, and makes the convex portion circulate a plurality of times along the inner periphery of the side wall of the concave portion. The metal sheet press forming method according to claim 1.   The metal plate press forming process according to claim 1, wherein the movement of the convex shape or the concave shape includes a spiral shift of the convex portion from a central portion of the concave portion toward a side wall. Method. A press forming apparatus for forming a plurality of protrusions on a metal plate using a die and a punch,
One of the die and the punch is a concave mold having a plurality of concave portions of a desired shape,
The other is a convex shape having a plurality of convex portions whose tip diameter is smaller than the minimum representative dimension of the concave portion,
At least one of the concave shape and the convex shape is arranged to be able to advance and retreat toward the other,
The metal plate is press-molded, wherein at least one of the concave mold and the convex mold is movable so that the convex section can relatively move along the inner periphery of the side wall of the concave section. apparatus.   5. The press molding apparatus according to claim 4, wherein a tip end portion of the convex portion is detachable.

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