JP2019155458A - Press molding method - Google Patents

Abstract

To provide a press molding method by which material yield can be improved without complication of processes.SOLUTION: A press molding method in which an expansion process P1 has: first axis processing (introduction step) P210 such that a processing roller 30 is pressed onto a face 1a on an inner side with respect to an end face 1b of a plate 1, thereby forming an introduction recess 15; and first stage overhang process P211 to fifth stage overhang process P215 in which the processing roller 30 is moved in a processing direction (horizontal direction) along a direction of the face 1a of the plate 1 from the introduction recess 15, thereby widening an end of the plate 1.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a press molding method for pressing a plate material.

  Conventionally, in press molding, molding is performed on a blank material (press molding material) obtained by processing a plate material to a predetermined size. For example, in the drawing, press molding is performed by pressing the product shape portion into the die side with a punch and applying plastic deformation in a state where the peripheral portion of the product shape portion in the blank material is pressed and restrained. In this case, the peripheral edge is constrained by sandwiching the peripheral edge of the blank between the die of the press molding machine and the blank holder or between the upper and lower blank holders. The peripheral portion of the blank material is a portion for restraining the position of the blank material in a molding process, that is, a so-called gripping margin. This gripping margin is necessary for press molding, but is a portion to be cut off in a later process. From the viewpoint of material yield, it is preferable that the marginal portion as a grip margin is as small as possible.

  For example, Patent Literature 1 discloses a press molding technique for improving the yield. Patent Document 1 constrains a predetermined portion of an end portion of a blank material obtained by the expansion step to obtain a blank material having a size suitable for predetermined press molding by at least partially expanding the end portion of the plate material. And a press forming method including press forming in a pressed state. Japanese Patent Application Laid-Open No. H10-228561 describes a step of applying pressure and extending in stages using a plurality of rollers having different widths in the course of the expansion step.

Japanese Patent No. 6240338

  Although the technique described in Patent Document 1 can achieve a good material yield improvement, in the process using a plurality of types of rollers having different widths, it is necessary to replace the rollers and the like. Become. Further, if rollers having the same width are used, there is no need to replace the rollers, and there is a possibility that the force applied to the plate material becomes local.

  An object of this invention is to provide the press molding method which can improve a material yield, without complicating a process.

  In the present invention, in order to obtain a blank material (for example, a blank material 110 to be described later) having a size suitable for a predetermined press molding, an end portion of a plate material (for example, a plate material 1 to be described later) is stretched out (for example, to be described later). An expansion process (for example, an expansion process P1 described later) that is pressurized and extended by the processing tool 10), and a molding process (for example, a molding process P2 that is described later) that is press-molded in a state where a predetermined portion of the end portion of the blank material is restrained. ), And the expanding step includes a processing roller (for example, a later-described surface) on an inner surface (for example, a later-described surface 1a) with respect to an end surface (for example, a later-described end surface 1b) of the plate material An introduction step (first shaft processing P210) for pressing the processing roller 30) to form an introduction recess (for example, an introduction recess 15 described later), and a processing direction along the surface direction of the plate material from the introduction recess It is related with the press molding method which has a projecting process (for example, the below-mentioned 1st stage projecting process P211-the 5th stage projecting process P215 mentioned later) which is moved by this and widens the edge part of the board.

  As a result, it is possible to effectively suppress the generation of shearing force and bending moment when the processing roller is brought into contact with the plate material, and the processing portion (for example, the portion that contacts the R portion of the die and its portion when performing the expansion process) The occurrence of cracks in the vicinity etc. can be effectively prevented.

  In the introducing step, after pressing the processing roller against the surface of the plate material, the processing roller is moved from the introduction recess to the outside of one end surface of the plate material, and the overhanging step (for example, a first step overhanging step P211 described later) Then, it is preferable that the processing roller is moved in the processing direction through the introduction recess from one side of the plate material at the same height as when the introduction recess is formed.

  Thereby, since the overhanging step is performed at the same height as when the introduction recess is formed, it is possible to effectively generate a partial variation such as a gap between a processing portion (for example, a later-described recess 32) to be continued from the introduction recess. Can be prevented.

  In the expansion step, the introduction is performed in a state where the height of the processing roller is set to a height that achieves a target widening ratio of 50% or more, which indicates a ratio to a target width after the end of the end of the plate material. After the first step overhanging step (for example, a first step overhanging step P211 described later) for moving the processing roller in the processing direction from the recess, and after the first step overhanging step, the processing roller is moved in the processing direction. It is preferable to perform a process (for example, a second-stage overhanging process P212 to a fifth-stage overhanging process P215 described later) by changing the height of the processing roller to achieve the target widening rate.

  As a result, both sides of the processing part (for example, the part contacting between the R part of the die and the end of the processing roller) can be extended in the plate material, and cracks are generated by preventing local extension due to the pressing force of the processing roller. Can be further prevented.

  After the first step overhanging step, a step of moving the processing roller in the processing direction (for example, a second step overhanging step P212 to a fifth step overhanging step P215 described later) is performed stepwise. It is preferable to carry out a plurality of times.

  Thereby, the variation of a process part can be suppressed, preventing local extension, and press molding can be performed with respect to a more homogeneous blank material.

  It is preferable that the processing roller is moved in the processing direction at the same height at least twice in the first step overhanging step in which the processing roller first enters from the introduction recess.

  Thereby, by re-forming the spring back generated by the processing of the first processing roller, it is possible to prevent the occurrence of constriction in the processed portion formed on the plate material, stress concentrates on the constriction after the first step overhanging process, It is possible to prevent the occurrence of cracks.

  It is preferable that the step of moving the processing roller in the processing direction at the same height at least twice after the first step overhanging step is performed a plurality of times while changing the height of the processing roller stepwise.

  As a result, the occurrence of constriction after the second overhanging step can be prevented, and the occurrence of cracks in each step can be further prevented.

  According to the press molding method of the present invention, the material yield can be improved without complicating the process.

It is process drawing which shows the press molding method as one Embodiment of this invention. It is a figure explaining the expansion process of this embodiment. It is a perspective view which shows typically the board | plate material processed with the processing tool of this embodiment. It is a figure which illustrates typically the force added to a board material when making a processing roller contact from an end surface by a comparative example. It is a figure which illustrates typically the force added to a board material when making the processing roller of this embodiment contact from the top. It is a figure which illustrates typically the multistep process by the processing roller of this embodiment. It is a graph which shows the relationship of the plate reduction rate with respect to the distance from the part pinched | interposed into a blank holder and die | dye to the center of the front-end | tip of a processing roller.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a process diagram showing a press molding method as one embodiment of the present invention.

  As shown in FIG. 1, in the press molding method of the present embodiment, an expansion step P <b> 1 for obtaining a blank material having a size suitable for predetermined press molding by expanding the end portion (predetermined partial region on the edge side) of the plate material. And the molding process P2 which press-molds in the state which restrained the edge part of the blank material obtained by the expansion process P1.

  The expansion process P1 of the present embodiment includes a smoothing process P200 and a leveling process P220. In the overhanging process P200, processing is performed in which the corresponding end portion of the plate member 1 is pressed and extended by the overhanging processing tool 10. In the leveling step P220, a process for flattening the corresponding portion of the plate material deformed into the non-planar shape by the overhanging step P200 is performed.

  First, the flow of the expansion process P1 will be described with reference to FIG. FIG. 2 is a view for explaining the expansion process P1 of the present embodiment step by step. (A) in FIG. 2 shows a cross section of the plate material 1 subjected to the expansion process P1. The plate material 1 is processed based on the widening range W1, which is a partial area set in advance.

  FIG. 2B shows a state in which the processing tool 10 performs a first shaft processing P210 and a first stage projecting step 211 described later in the projecting process P200 in the expansion process P1. By the first shaft processing P210 and the first step overhanging step 211, the widening range W1 at the end of the plate 1 is pressurized and extended by the processing tool 10. A concave portion 32 is formed in the plate material 1, and the back side of the concave portion 32 becomes a convex portion 31. The depth from the top surface of the plate 1 shown in FIG. 2B to the bottom of the recess 32 is defined as an overhanging depth d1.

  FIG. 2C shows a state in which the overhang depth is deepened by multi-stage processing of the processing roller 30 described later. The depth d1 shown in (b) in FIG. 2 is formed through the multi-stage processing of the processing tool 10 to form a recess 32 having an overhang depth d2 that is deeper than the overhang depth d1. After the first shaft machining P210 and the first stage overhanging process P211, a second stage overhanging process P212 and a fifth stage overhanging process P215 are sequentially performed. Note that the number of multi-stage machining is not limited, and is adjusted as appropriate depending on the machining target.

  (D) in FIG. 2 shows a cross section of the plate material 1 as a result of the expansion step P1 in which the end portion is extended in the overhanging step P200 and then flattened in the leveling step P220. Yes. In this state, the width of the end portion side of the plate material 1 is widened to form a blank material 110 having a size suitable for predetermined press molding. The portion 111 protruding outward from the product shape portion as a so-called gripping margin of the blank material 110 is relatively reduced in thickness, but the original thickness size is maintained in the product shape portion. W2 is the sum of the widths of the hold devices 11 and 12, which will be described later, and the length obtained by extending the plate 1.

  In the expansion process P1, as described above, the end portion of the plate material 1 is at least partially expanded to obtain the blank material 110 having a size suitable for predetermined press molding.

  In the molding step P2, the overhanging portion 111 serving as a grip margin for the blank 110 formed on the peripheral edge of the plate 1 as described above is placed between the die of the press molding machine and the blank holder or between the upper and lower blank holders. The product is constrained so as to be sandwiched, and the product shape portion of the blank material is pushed into the die side with a punch, and press molding is performed as usual. As a result, while applying a plate material smaller than a normal blank material as a press molding plate material, the product shape portion is the same size as usual while forming a constrained portion corresponding to a gripping margin in the above-described expansion process P1. A blank 110 is secured. Therefore, it is possible to improve the material yield while minimizing the dimensional error at the product shape part during press molding.

  Next, the configuration of the processing tool 10 described in (b) and (c) of FIG. 2 will be described with reference to FIG. FIG. 3 is a perspective view schematically showing the plate 1 processed by the processing tool 10 of the present embodiment. The processing tool 10 mainly includes a pair of holding devices 11 and 12 that sandwich an end portion (a predetermined partial region on the end edge side) of the plate member 1 from above and below with a certain interval, and a processing roller 30. Prepare.

  The hold device 11 includes a blank holder 21 and a die 22 that are paired up and down. The blank holder 21 has a bead forming convex portion 210 projecting downward on the lower surface thereof. The die 22 has a bead forming recess 220 formed on the upper surface thereof according to the position of the bead forming protrusion 210. Each of the bead forming convex portion 210 and the bead forming concave portion 220 is formed to be elongated in a predetermined direction. Further, the end of the upper portion of the die 22 on the processing roller 30 side is formed in an R shape (hereinafter, referred to as an R portion 221).

  Similarly, the hold device 12 includes a blank holder 23 and a die 24 that are paired up and down. The blank holder 23 has a bead forming convex portion 230 protruding downward on the lower surface thereof. The die 24 has a bead forming recess 240 formed on the upper surface thereof. Each of the bead forming convex portion 230 and the bead forming concave portion 240 is formed to be elongated in a predetermined direction. Further, the end portion on the processing roller 30 side in the upper portion of the die 24 is formed in an R shape (hereinafter referred to as an R portion 241).

  The holding device 11 is arranged on one side of the widening range W1 in the plate material 1, and the holding device 12 is arranged on the other side of the widening range W1 in the plate material 1. In the drawing, the holding device 12 is located on the end face 1 b side of the plate 1. The holding device 11 and the holding device 12 restrain both sides of the widening range W1 in the plate 1.

  The holding device 11 sandwiches the end portion of the plate 1 with a constant load by the blank holder 21 and the die 22. The plate member 1 is firmly restrained while a part 101 of the upper surface is pressed by the bead forming convex portion 210 of the blank holder 21 and a bead portion 102 protruding downward along the outer shape of the bead forming convex portion 210 is formed. The bead portion 102 is housed in the bead forming recess 220 of the die 22.

  Further, the holding device 12 sandwiches the end portion of the plate 1 with a constant load by the blank holder 23 and the die 24. The plate 1 is firmly restrained while a part 103 of the upper surface is pressed by the bead forming convex portion 230 of the blank holder 23 and a bead portion 104 projecting downward along the outer shape of the bead forming convex portion 230 is formed. . The bead portion 104 is accommodated in the bead forming recess 240 of the die 24.

  The processing roller 30 is a roller having a narrower width than the interval between the hold device 11 and the hold device 12, and is positioned between the hold device 11 and the hold device 12. The processing roller 30 is configured to be movable in a direction along the direction of the surface 1a of the plate 1 (hereinafter referred to as a processing direction) and to be adjustable in height with respect to the plate 1. In addition, the height of the processing roller 30 is a distance with respect to the board | plate material 1, and does not necessarily mean that the height of the processing roller 30 is limited to an up-down direction.

  The processing roller 30 moves in the processing direction while pressing the plate material 1 from the upper surface and applying a load while the plate material 1 is restrained by the hold device 11 and the hold device 12, and extends the plate material 1 while deforming it into a concave shape. . As a result, a groove-like recess 32 is formed in the plate material 1. In addition, since the board | plate material 2 is restrained by the holding apparatus 11 and the holding apparatus 12, it does not shift | deviate to the axial direction (left-right direction in a figure) even while the processing roller 30 is pressed.

  Next, the first shaft machining P210 in the overhanging process P200 will be described while comparing the comparative example of FIG. 4 and the present embodiment of FIG.

  FIG. 4 is a diagram schematically illustrating the force applied to the plate material 1 when the processing roller 30 is brought into contact with the end portion in the comparative example. In FIG. 4A, the initial position of the processing roller 30 is set to a height corresponding to the depth (projection amount) of the recess 32 at a position facing the end surface 1 b of the plate 1. Shown visually.

  The processing roller 30 advances in the direction of the broken arrow while maintaining the height of the initial position, contacts the end surface 1b of the plate material 1, and advances in the moving direction while pressing the end surface 1b of the plate material 1 downward. 32 is formed. At this time, a shearing force F in the traveling direction of the processing roller 30 is applied to the plate 1 by the pressure applied by the processing roller 30. The shear force F increases as the penetration angle θ formed by the tangential direction of the processing roller 30 and the planar direction of the plate 1 increases in side view. That is, the greater the overhang and the deeper the recess 32 formed in the plate 1, the greater the penetration angle and the greater the shear force F. That is, the higher the overhang, the greater the shearing force F and the more excessive force is applied to the plate material 1.

  In FIG. 4B, an initial state in which pressurization is started when the processing roller 30 contacts the end surface 1b of the plate 1 is shown in a plan view. The longer the distance L1 from the center of the processing roller 30 to the holding device 11 and the holding device 12 on both sides, the greater the moment of force with the center of the processing roller 30 as the power point. A force to rotate the plate 1 in the direction of the white arrow works, and the bead portions 102 and 104 tend to break. That is, the wider the widening range, the easier it is to break.

  Therefore, in the present embodiment, by devising the operation of the first shaft processing P210 at the time of the initial contact between the processing roller 30 and the plate material 1, no breakage occurs even if the overhang amount is increased and the widening range is expanded. Realized the processing method. The operation of the first axis machining P210 of this embodiment will be described with reference to FIG. FIG. 5 is a diagram schematically illustrating the force applied to the plate material 1 when the processing roller 30 of the present embodiment is brought into contact with the top.

  In FIG. 5A, the operation of the first shaft machining P210 of the machining roller 30 of the present embodiment is shown in a side view. In FIG. 5B, the state when the processing roller 30a contacts the plate material 1 in the first shaft processing P210 is shown in plan view.

  The initial position of the processing roller 30 in the first shaft processing P <b> 210 is set above the plate material 1. The processing roller 30 at the initial position faces the surface 1 a of the plate 1. The initial position is set at a position facing the surface 1 a at a position where the center of the processing roller 30 is separated from the end surface 1 b of the plate 1 by a predetermined distance. Note that the predetermined distance is preferably separated by at least the diameter of the processing roller 30 so that the processing roller 30 and the end surface 1b of the plate 1 do not overlap in the vertical direction.

  As shown to (a) in FIG. 5, in the 1st axis | shaft process P210, the processing roller 30 of an initial position descends from the upper direction of the board | plate material 1, and contacts the surface 1a of the board | plate material 1. FIG. The processing roller 30a that has come into contact with the surface 1a of the plate member 1 is lowered to a depth at which the concave portion 32 is formed according to the set overhang amount. Thereafter, the processing roller 30b moves to the outside of the end surface 1b of the plate 1 while maintaining its height. The moving direction of the processing roller 30 is the processing direction, but the direction in which the processing roller 30 advances in the next process is a reverse movement.

  As shown in FIG. 5B, in the first shaft processing P <b> 210, the processing roller 30 comes into contact with the inner surface 1 a of the plate material 1, so that the force F <b> 2 due to the load of the processing roller 30 presses the plate material 1. Although applied in the (backward direction of the paper surface), shearing force and moment of force that tear the plate 1 as described with reference to (a) in FIG. 4 are not generated. Thereby, the breakage of the plate 1 when the processing roller 30 is in contact can be effectively prevented.

  The introduction recess 15 is formed in a part of the end surface 1b of the plate 1 by the first shaft processing P210 described above. After the first shaft processing P210, the processing roller 30 enters from the introduction recess 15 and an overhanging process is performed. The overhanging process includes a first overhanging process P211, a second overhanging process P212, a third overhanging process P213, a fourth overhanging process P214, and a five-stage overhanging process (final stage) according to the target overhang amount to be formed on the plate material 1. (Overhanging process) P215 and a plurality of times. In the present embodiment, the example in which the projecting process is performed five times from the first projecting process P211 to the fifth projecting process P215 has been saved, but the target projecting amount and the widening range W1 to be formed on the plate material 1 are saved. The number of overhanging steps is appropriately set depending on the configuration of the processing tool 10 and the like.

  Next, multi-step processing performed after the first axis machining P210 will be described with reference to FIG. FIG. 6 is a diagram for schematically explaining the multi-stage processing by the processing roller 30 of the present embodiment. In FIGS. 6A to 6C, the multi-stage processing of different methods is performed from the first stage. It is shown how it went. In any of the examples (a) to (c) in FIG. 6, the height of the processing roller 30 in the first step entry / exit step P211 is the same as the height of the processing roller 30 in the first shaft processing P210. Is set. Further, it is assumed that the left side of the drawing is the first step, the center of the drawing is the second step, and the right side of the drawing is the last step.

  In the multi-stage process of FIG. 6A, the processing roller 30 reciprocates while maintaining the height at all stages. More specifically, in the first step overhanging step P211, the processing roller 30 is reciprocated relative to the plate material 1. That is, the processing by the processing roller 30 is performed twice in the forward path and the return path in the first stage overhang process P211. In the second step overhanging step P212, the processing roller 30 is moved downward relative to the first step overhanging step P211. Then, the processing roller 30 reciprocates in a state where the position deeper than the first step overhanging process P211 is maintained, and processing by the processing roller 30 is performed twice in the forward path and the return path. The same processing is performed for the third and fourth stages, and the processing is performed twice in the forward and return paths in the final stage.

  In the multi-stage process (b) in FIG. 6, the processing of the plate material 1 by the processing roller 30 is performed once at all stages. More specifically, in the first step overhanging process P211, the processing by the processing roller 30 is performed only once on the forward path for the plate material 1. In the second step overhanging step P212, the return path is processed while the processing roller 30 is moved downward as compared with the first step overhanging step P211. Thereafter, until the fifth step overhanging step P215, every time the step changes, the position of the processing roller 30 is lowered, and the processing is performed by the forward path or the backward path.

  In the multi-stage process (c) in FIG. 6, only the first stage overhang process P211 is performed twice for the forward path and the backward path, and thereafter, the processing is performed once for the forward path and the backward path. The first step overhanging process P211 in which the first processing is performed. The process is the same as (a) in FIG. 6, and the second and subsequent second overhanging process P212 is the same process as (b) in FIG.

  The process (a) in FIG. 6 is advantageous from the viewpoint of reducing the load on the plate 1 when the processing roller 30 contacts, and the process (b) in FIG. 6 is advantageous from the viewpoint of shortening the cycle time. is there. In the process of (c) in FIG. 6, the first stage having a large influence in the multi-stage process is reciprocated, so that the load on the plate 1 is reduced while the process after the second stage is performed once in the forward path or the backward path. The cycle time is shortened while reducing. The multi-stage processing described in (a) to (c) in FIG. 6 is appropriately selected according to the required product specifications, etc., thereby reducing the burden on the plate material 1 and shortening the cycle time. It can be realized accordingly.

  As described above, in the expansion process, after the introduction recess 15 is formed in the first shaft processing P210, the plate material 1 is deformed and extended into a planar shape (concave shape) through a plurality of steps. Then, a leveling process is performed in the next leveling process P220. The leveling process P220 is performed by a plurality of rollers (not shown) that sandwich the plate material 1. For example, like the leveling process of Patent Document 1 of the prior art, a plurality of large and small rollers may be arranged so as to sandwich the plate material, and the leveling process P220 may be performed by pressing the rollers. The expansion process P1 ends when the leveling process P220 is completed. After the expansion process P1, the plate 1 that has become the blank 110 is press-molded in the molding process P2.

  The series of flows of the press molding method of the present embodiment has been described above. Next, the height of the processing roller 30 set in the first overhanging process P211 will be described. The height (projection amount) of the convex portion 31 of the plate 1 is determined by the height of the processing roller 30, and the widening after the projecting step is determined according to the height of the convex portion 31. For example, theoretically, the height (projection amount) of the processing roller 30 can be considered to be proportional to the widening rate. In this case, assuming that the widening rate is y and the overhang amount is x, the overhang amount x is determined if the height of the processing roller 30 is determined. Therefore, the widening rate can be calculated by y = ax + b. The coefficient a and the intercept b are determined depending on the plate material, the configuration of the processing tool 10, and the like.

  Based on the target width after completion of the overhanging process P200, the height of each process of the processing roller 30 is set. In the present embodiment, in order to prevent local extension of the plate material 1, the width (width expansion ratio) widened by the first step overhanging step P <b> 211 is set to each time of the second step overhanging step P <b> 212 to the fifth step overhanging step P <b> 215. The height of each process of the processing roller 30 is set so as to be the largest value compared with the width (width expansion ratio) widened by.

  Next, the reason why the widening ratio is set to be the largest in the first step overhang process P211 will be described. FIG. 7 is a graph showing the relationship between the plate reduction ratio and the distance from the portion sandwiched between the blank holder 21 and the die 22 to the center of the tip of the processing roller 30. In the graph of FIG. 7, the pitch from the end of the bead portion 102 on one side of the plate 1 to the center of the processing roller 30 is shown. The portion where the pitch from the end portion of the bead portion 102 is 0 is the position in front of the R portion 221 in the die 22 (corresponding to the position of the lead line of the R portion 221 in (b) and (c) in FIG. 2). To do). Further, the portion where the pitch is 18 is the center position of the processing roller 30. That is, (b) and (c) in FIG. 2 and a half range of the recess 32 in FIG. 3 are shown.

  In the graph of FIG. 7, in the case of a single process in which the height of the processing roller 30 is set so that a predetermined overhanging amount (for example, 8 mm) is achieved in one overhanging step, a plurality of predetermined overhanging amounts are shown. In the case of a plurality of treatments in which a plurality of steps are performed so as to be achieved in the overhanging step (2 mm for the first time, 4 mm for the second time, 6 mm for the second time, and 8 mm for the second time). As shown in this graph, when a predetermined overhanging amount (for example, 8 mm) is achieved in one overhanging process, the elongation of the portion of the die 22 that contacts the R portion 221 is increased, and the processing roller 30. It can be seen that the plate reduction rate in the vicinity of the end of the plate decreases (see the white arrow in the graph).

  In other words, it can be understood that local elongation can be prevented by processing with the processing roller 30 with a large overhang amount at a time within a certain range. On the other hand, the target widening may not be achieved or the burden on the plate 1 may be increased by a one-time overhanging process. Therefore, in the present embodiment, the height of the processing roller 30 is set so as to achieve more than half of the target widening ratio in the first stage overhanging step. The target widening rate means the length of the plate material before and after widening. For example, when a 100 mm processed portion is set to 120 mm, the target widening ratio is 20%. In this case, in the first overhanging process P211, the height of the processing roller 30 is set so as to be widened at a widening rate (for example, 12%) that is more than half of the target widening rate of 20%. As a method for obtaining the height of the processing roller 30 from the height of the widening rate, an appropriate method such as the above-described formula can be used.

  After the first step overhanging process P211, the height of the processing roller 30 is changed several times in the second step overhanging step P212 to the fifth step overhanging step P215, and the overhanging process is performed.

  Next, the effect of the reciprocating processing of the processing roller 30 described in (a) and (c) of FIG. 6 will be described. In fact, when compared with one-time machining (only the forward path) and two-time machining (outward-path and backward path), the center of the one-time machining is less, but the center is better in the two-time machining. It turned out that it was widened. This is because the spring back occurs after the processing roller 30 moves in the processing direction in the one-time processing, but even if the spring back occurs in the two-time processing, the backward movement is widened by the processing roller 30 having the same height. It is thought to be done. If the next stage is reached after springback has occurred, the difference between the actual molding allowance and the designed molding allowance will be large, and the overhang amount projected by the processing roller 30 in the next stage will normally be It will be easier to cause constriction. Therefore, it can be seen that the twice processing is preferable from the viewpoint of improving the quality.

According to the above embodiment, the following effects are obtained.
The expansion process P1 of the press molding method includes a first shaft processing (introduction process) P210 in which the processing roller 30 is pressed against the surface 1a on the inner side of the end surface 1b of the plate 1 to form the introduction concave portion 15; Press forming method including first step overhanging step P211 to fifth step overhanging step P215 for widening the end of plate 1 by moving 30 in the processing direction (horizontal direction) along the direction of surface 1a of plate 1 About.
Thereby, generation | occurrence | production of the shearing force and bending moment when making the process roller 30 contact the board | plate material 1 can be suppressed effectively, and the process part (for example, R part 221 and die 22 of the die | dye 22) when performing the expansion process P1 can be suppressed. It is possible to effectively prevent the occurrence of cracks at a portion in contact with the R portion 241 of the die 24 and the vicinity thereof.

Further, in the first shaft processing P210 of the present embodiment, after the processing roller 30 is pressed against the surface 1a of the plate material 1, the processing roller 30 is moved from the introduction recess 15 to the outside of the end surface 1b on one side of the plate material 1, and the first step overhanging step In P211, the processing roller 30 is moved in the processing direction from one side of the plate 1 through the introduction recess 15 at the same height as when the introduction recess 15 is formed.
Thereby, since the overhanging step is performed at the same height as when the introduction recess 15 is formed, it is possible to effectively prevent the occurrence of partial variations such as between the introduction recess 15 and the recess 32 continuing.

Further, in the expansion step P1 of the present embodiment, the height of the processing roller 30 is set to a height that achieves 50% or more of the target widening ratio indicating the ratio to the target width after the completion of the fifth step overhanging step P215. After the first step overhanging step P211 in which the processing roller 30 is moved in the processing direction from the introduction recess 15 and the first step overhanging step P211, the second step overhanging steps P212 to P5 in which the processing roller 30 is moved in the processing direction. The step overhanging step P215 is performed by changing the height of the processing roller 30 to achieve the target widening rate.
Thereby, in the plate material 1, it is possible to extend a portion between the R portion 221 of the die 22 or the R portion 241 of the die 24 and the end portion of the processing roller 30, thereby preventing local extension due to the pressing of the processing roller 30. Thus, cracks caused by local elongation can be further prevented.

In the present embodiment, after the first step overhanging step P211, the second step overhanging step P212 to the fifth step overhanging step P215 are performed a plurality of times while changing the height of the processing roller stepwise, and each step The height of the processing roller 30 is set so that the widening is equal to or less than 20% of the target widening rate.
Thereby, variation in a processed part can be suppressed while local extension is prevented, and press molding can be performed on a more uniform blank material 110.

In the present embodiment, the processing roller 30 is moved in the processing direction at the same height at least twice in the first overhanging step P211 in which the processing roller 30 first enters from the introduction recess 15.
As a result, by re-forming the spring back generated by the processing of the first processing roller 30, it is possible to prevent the processing portion formed on the plate 1 from being constricted, and the constriction is stressed after the first overhanging step P211. It is possible to prevent the occurrence of a situation in which cracks concentrate and cracks occur.

In the present embodiment, after the first step overhanging step P211, the second step overhanging step P212 to the fifth step overhanging step P215 may be performed a plurality of times while changing the height of the processing roller 30 stepwise.
Thereby, it is possible to prevent the constriction after the second overhanging process P212 and to further prevent the occurrence of a crack in each process.

  As mentioned above, although preferable embodiment of this invention was described, this invention is not restrict | limited to the above-mentioned embodiment, It can change suitably. For example, in the above embodiment, the height of the processing roller 30 is set to the same height in the first shaft processing P210 and the first step overhanging process, but the height of the processing roller 30 is set higher than that of the first shaft processing P210. The first step overhanging step can also be performed by lowering.

DESCRIPTION OF SYMBOLS 1 Board | plate material 15 Introduction recessed part 30 Processing roller 110 Blank material P1 Expansion process P2 Forming process P200 Overhang process P210 1st axis | shaft process (introduction process)
P211 First stage overhanging process P212 Second stage overhanging process P213 Third stage overhanging process P214 Fourth stage overhanging process P215 5th stage overhanging process

Claims (6)

In order to obtain a blank material having a size suitable for a predetermined press molding, an expansion process in which an end portion of a plate material is pressurized and extended by an overhanging tool, and press molding is performed in a state where a predetermined portion of the end portion of the blank material is constrained. A press forming method comprising:
The expansion process includes
An introduction step of forming an introduction recess by pressing a processing roller against the inner surface of the end surface of the plate material;
And a projecting step of widening an end portion of the plate material by moving the processing roller from the introduction recess in a processing direction along a surface direction of the plate material. In the introduction step, after pressing the processing roller against the surface of the plate material, the processing roller is moved from the introduction recess to the outside of one end surface of the plate material,
2. The press molding method according to claim 1, wherein in the projecting step, the processing roller is moved in the processing direction from one side of the plate material through the introduction recess at the same height as when the introduction recess is formed. The expansion process includes
The processing roller is moved from the introduction recess in a state where the height of the processing roller is set to a height that achieves a half or more of the target widening ratio indicating the ratio to the target width after the end of the sheet material overhanging process. A first overhanging step of moving in the processing direction;
The press molding method according to claim 1 or 2, wherein after the first step projecting step, the step of moving the processing roller in the processing direction is performed by changing the height of the processing roller to achieve the target widening ratio.   The press molding method according to claim 3, wherein the step of moving the processing roller in the processing direction after the first step overhanging step is performed a plurality of times by changing the height of the processing roller stepwise.   The press molding method according to any one of claims 1 to 4, wherein the processing roller is moved in the processing direction at the same height at least twice in a first step overhanging step in which the processing roller first enters from the introduction recess. .   6. The press according to claim 5, wherein after the first step overhanging step, the step of moving the processing roller in the processing direction at least twice at the same height is performed a plurality of times by changing the height of the processing roller stepwise. Molding method.

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