JP2016168619A - Bottomed cylindrical component and manufacturing method for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bottomed cylindrical component of high molding height and a manufacturing method thereof only by near flexure molding by using cold press molding which not only dispenses with paired special works to each of both dies (die and punch) but also is capable of mass production from blank materials.SOLUTION: A manufacturing method for a bottomed cylindrical component includes a premolding process and a permanent molding process for forming a square cylindrical component as a bottomed cylindrical component by setting a blank material 1 with folds 1d, 1e, 1f formed by the premolding process between the die 4 and the punch 3 to perform press molding. When a rib 1g that overhangs outward from between adjacent vertical walls 1b of the square cylindrical component in a planar view upon press molding in the permanent molding process, a corner part 4c of the inner side face of the die 4 is provided with a groove 4f.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a bottomed cylindrical part having a high molding height formed by press molding from a blank material and a method for manufacturing the same.

  In many cases, a fuel tank, a battery tray, or the like mounted on a vehicle forms a substantially cylindrical or square cylindrical part with a bottom by press deep drawing from a plate material. Since such fuel tanks and battery trays are also required to have a watertight structure, they are integrally formed by press molding and the internal capacity is desired to be as large as possible. In addition, there is a desire to make the molding height as high as possible.

  However, the smaller the corner R and the higher the molding height, there is a problem that in the press deep drawing, fracture occurs and molding becomes difficult.

  As a technique for solving such a problem, a technique for reducing the drawing resistance and improving the molding limit has been proposed (for example, see Patent Document 1). This technology constrains the material with a blank holder and a die mold, provides a recess in a part of the die, and forms a folded flange by actively generating wrinkles in this part, thereby reducing the drawing resistance of the corner flange. By reducing this, the molding limit is improved.

  Further, as another technique for solving the above problems, there has been proposed a molding method for forming a pair of folded flanges folded inside the corner portion of the cylindrical part without using a blank holder (for example, Patent Documents). 2). Since this technique can be manufactured by bending without substantially drawing, it can be expected to greatly improve the molding limit.

Japanese Patent No. 4985909 Japanese Patent No. 3454656

  However, since the technique disclosed in Patent Document 1 is formed by deep drawing to the last, there is a limit to the reduction of drawing resistance, and a very deep molded product (that is, one having a high molding height) is required. In the case of molding, there is still a problem that breakage occurs.

  In addition, the technique disclosed in Patent Document 2 is to provide a special guide projection on the die to form a pair of folded flanges folded inside the corner portion, and to provide a corresponding relief groove in the punch. There was a problem that special tools for pairing were required for both molds. In addition, since the blank material itself has no guide as a starting point for bending to form a pair of folded flanges in the area that becomes the corner portion after the press molding is completed, a large bending resistance is generated in the blank material itself. End up. In addition, in the configuration based on such a principle, it is not only difficult to prepare a pair of dies and punches for forming two or more pairs of folded flanges at the corner portion during press molding, but also the folded flanges. There was a problem that the formation itself was not stable.

  The object of the present invention is that it is not necessary to perform a pair of special work on both dies (dies and punches), but only a substantially bend forming using a cold press forming capable of mass production from a blank material. It is an object of the present invention to provide a bottomed cylindrical part having a high molding height and a method for producing the same.

In order to achieve this object, the bottomed tubular part according to the first invention is:
A bottomed cylindrical part having a bottom part and a plurality of vertical walls rising from the periphery of the bottom part,
This bottomed cylindrical part is formed by press-molding a blank material, and has a plurality of corner portions that are integrated with the bottom portion and the adjacent vertical wall,
The corner portion is provided with one or more ribs protruding outward or inward from between the adjacent vertical walls in plan view,
This rib consists of a pair of folded flanges folded back at the crease formed in advance in the blank material so as to divide the region to be the corner portion into approximately equal parts,
The amount of the rib protruding outward or inward increases from the bottom toward the open end of the vertical wall in a side view, and
The rib is a bottomed tubular part characterized in that the rib is not provided with a flange extending outward from an open end of the rib in a plan view.

The bottomed tubular part according to the second invention is the bottomed tubular part according to the first invention,
The corner portion has a substantially arc shape in plan view, and 2 to 4 ribs are formed in the corner portion having the substantially arc shape. Here, the substantially arc shape indicates a curved surface shape having a mathematically constant curvature radius, a curved surface shape in which straight portions are joined, or a polygonal shape close to a curved surface shape. The rib is formed so as to protrude from such a substantially arc-shaped corner.

The bottomed tubular part according to the third invention is the bottomed tubular part according to the second invention,
In the bottom portion, concave portions or convex portions that are continuous in a plan view are formed corresponding to the ribs projecting outward or inward from the substantially arc-shaped corner portion, respectively. The definition of the substantially arc shape is as described above.

The bottomed tubular part according to the fourth invention is the bottomed tubular part according to the third invention,
The concave portion or the convex portion provided in the bottom portion is formed radially from the center of the corner portion having the substantially arc shape in a plan view. The definition of the substantially arc shape is as described above.

The bottomed tubular part according to the fifth invention is the bottomed tubular part according to any one of the first to fourth inventions,
A flange extending outward from the open end of the vertical wall is provided.

A manufacturing method of a bottomed cylindrical part according to a sixth invention is a manufacturing method of manufacturing a bottomed cylindrical part according to the first invention,
The area and the vertical wall that become the bottom using a preforming mold for the blank material having the areas that become the bottom, the plurality of vertical walls, and the plurality of corners of the bottomed cylindrical part after press molding A preforming step for forming a crease at a boundary of the region to be formed, a boundary between the region to be the vertical wall and the region to be the corner portion, and a position for substantially equally dividing the region to be the corner portion; ,
A main forming step of forming the bottomed cylindrical part by setting the blank material in which the crease is formed by this pre-forming step to correspond to the shape of the blank material, setting between the die and the punch, and press forming; Have
In this final molding process,
When one or more ribs projecting outward from between the adjacent vertical walls of the bottomed cylindrical part in a plan view are formed during press molding, grooves are provided in corners of the die. And
When one or more ribs projecting inward from between the adjacent vertical walls of the bottomed cylindrical part in a plan view are formed during press molding, grooves are formed in corner portions of the outer surface of the punch. It is the structure provided, It is a manufacturing method of a bottomed cylindrical component characterized by the above-mentioned.

A manufacturing method of a bottomed cylindrical part according to a seventh aspect of the present invention is the method of manufacturing a bottomed cylindrical part according to the sixth aspect of the invention,
In the preforming step, the number of positions for forming the folds in order to divide the region to be the corner portion into substantially equal parts is 3 to 7.

The manufacturing method of the bottomed cylindrical part according to the eighth invention is the manufacturing method of the bottomed cylindrical part according to the sixth or seventh invention,
The inside of the corner portion of the die is formed so as to have an inscribed circle radius of curvature R1 in plan view, and the corner portion of the outer surface of the punch is a plane corresponding to the inscribed circle of the corner portion of the die. The clearance between the punch and the die represented by R1-R2 is 100% or more and 200% of the plate thickness of the blank material. It is set as follows.
Here, R1> R2.

A method for manufacturing a bottomed cylindrical part according to a ninth aspect of the invention is a method for manufacturing a bottomed cylindrical part according to the eighth aspect of the invention,
In the main forming step,
When one or more ribs projecting outward from between the adjacent vertical walls of the bottomed cylindrical part in a plan view are formed during press molding, grooves are provided in corner portions of the bottom surface of the die. And
When one or more ribs projecting inward from between the adjacent vertical walls of the bottomed cylindrical part in plan view are formed during press molding, a groove is provided in a corner portion of the bottom surface of the punch. It is characterized by.

A method for manufacturing a bottomed cylindrical part according to a tenth aspect of the invention is a method for manufacturing a bottomed cylindrical part according to the ninth aspect of the invention,
The grooves provided in the corner portion of the bottom surface of the die or the corner portion of the bottom surface of the punch are formed radially from the center of each corner portion.

The manufacturing method of the bottomed cylindrical part according to the eleventh aspect of the invention is the manufacturing method of the bottomed cylindrical part according to any one of the sixth to tenth aspects of the invention,
A flange is provided on the upper end side of the punch so as to extend outward from an outer surface excluding a corner portion of the punch.

As described above, the bottomed cylindrical part of the present invention is
A bottomed cylindrical part having a bottom part and a plurality of vertical walls rising from the periphery of the bottom part,
This bottomed cylindrical part is formed by press-molding a blank material, and has a plurality of corner portions that are integrated with the bottom portion and the adjacent vertical wall,
The corner portion is provided with one or more ribs protruding outward or inward from between the adjacent vertical walls in plan view,
This rib consists of a pair of folded flanges folded back at the crease formed in advance in the blank material so as to divide the region to be the corner portion into approximately equal parts,
The amount of the rib protruding outward or inward increases from the bottom toward the open end of the vertical wall in a side view, and
Since the rib does not have a flange that extends outward from the open end of the rib in plan view,
It is not necessary to perform special work to make a pair on both dies (dies and punches), but using high-temperature cold press forming that can be mass-produced from blank materials, the forming height is high only by bending. A bottomed cylindrical part can be realized.

In addition, the manufacturing method of the bottomed cylindrical part of the present invention,
The area and the vertical wall that become the bottom using a preforming mold for the blank material having the areas that become the bottom, the plurality of vertical walls, and the plurality of corners of the bottomed cylindrical part after press molding A preforming step for forming a crease at a boundary of the region to be formed, a boundary between the region to be the vertical wall and the region to be the corner portion, and a position for substantially equally dividing the region to be the corner portion; ,
A main forming step of forming the bottomed cylindrical part by setting the blank material in which the crease is formed by this pre-forming step to correspond to the shape of the blank material, setting between the die and the punch, and press forming; Have
In this final molding process,
When one or more ribs projecting outward from between the adjacent vertical walls of the bottomed cylindrical part in a plan view are formed during press molding, grooves are provided in corners of the die. And
When one or more ribs projecting inward from between the adjacent vertical walls of the bottomed cylindrical part in a plan view are formed during press molding, grooves are formed in corner portions of the outer surface of the punch. Because it is provided configuration,
It is not necessary to perform special work to make a pair on both dies (dies and punches), but using high-temperature cold press forming that can be mass-produced from blank materials, the forming height is high only by bending. The manufacturing method which can manufacture a bottomed cylindrical part can be provided.

It is a schematic plan view explaining the blank material before shape | molding into the bottomed cylindrical component of Embodiment 1 of this invention. FIG. 2 is a partially enlarged perspective view of a preforming mold according to the first embodiment. FIG. 2 is a partially enlarged view of the blank material before and after the preforming according to the first embodiment, (a) is an enlarged view of a portion A before the preforming shown in FIG. 1, and (b) is a perspective view after the preforming. It is a model perspective view which shows the positional relationship of the punch at the time of this shaping | molding which concerns on the Embodiment 1, the blank material after preforming, and die | dye. FIG. 5 is a detailed shape dimension diagram of the punch and the die shown in FIG. 4. It is a deformation | transformation state figure which shows the deformation | transformation state of the blank material in the main shaping | molding which concerns on the same Embodiment 1. FIG. It is a schematic plan view explaining the blank material before shape | molding into the bottomed cylindrical component of Embodiment 2 of this invention. FIG. 6 is a partially enlarged perspective view of a preforming mold according to the second embodiment. It is a partially enlarged view of the blank material before and after the preforming according to the second embodiment, (a) is an enlarged view of a portion B before the preforming shown in FIG. 7, and (b) is a perspective view after the preforming. It is a model perspective view which shows the positional relationship of the punch at the time of the main shaping | molding which concerns on the same Embodiment 2, the blank material after preforming, and die | dye. It is a deformation | transformation state figure which shows the deformation | transformation state of the blank material in the main shaping | molding which concerns on the same Embodiment 2. FIG. It is a schematic plan view explaining the blank material before shape | molding in the bottomed cylindrical component of Embodiment 3 of this invention. FIG. 10 is a partially enlarged perspective view of a preforming mold according to the third embodiment. FIG. 13 is a partially enlarged view of the blank material before and after the preforming according to the third embodiment, (a) is an enlarged view of a portion C before the preforming shown in FIG. 12, and (b) is a perspective view after the preforming. It is a model perspective view which shows the positional relationship of the punch at the time of this shaping | molding which concerns on the same Embodiment 3, the blank material after preforming, and die | dye. FIG. 16 is a detailed shape dimension diagram of the punch and the die shown in FIG. 15. It is a deformation | transformation state figure which shows the deformation | transformation state of the blank material in the main shaping | molding which concerns on the same Embodiment 3. FIG.

  Hereinafter, the present invention will be described in detail while illustrating embodiments.

(Embodiment 1)
FIG. 1 is a schematic plan view for explaining a blank material before being formed into a bottomed cylindrical part according to Embodiment 1 of the present invention, and FIG. 2 is a partially enlarged perspective view of a preforming mold according to Embodiment 1; 3 is a partially enlarged view of the blank material before and after preforming according to the first embodiment, (a) is an enlarged view of a portion A before the preforming shown in FIG. 1, and (b) is a perspective view of the A portion after the preforming. FIG. 4 is a schematic perspective view showing the positional relationship between the punch at the time of the main molding according to the first embodiment, the blank material after the preliminary molding and the die, and FIG. 5 is a detailed shape and dimension diagram of the punch and the die shown in FIG. FIG. 6 is a deformation state diagram showing a deformation state of the blank material during the main forming according to the first embodiment.

  In FIG. 1, 1 is a blank of 800 mm long × 1000 mm wide × 1.0 mm thick made of a 6000 series aluminum alloy before cold press forming (hereinafter also simply referred to as “press forming”). A region that becomes the bottom of a rectangular cylindrical part as a bottomed cylindrical part after molding, 1b is a region that becomes a plurality of (four) vertical walls of the rectangular cylindrical part after press molding, and 1c is a plurality of rectangular cylindrical parts after press molding ( This is the area that becomes the corner part of (4).

  FIG. 2 shows the blank 1 having the regions 1a, 1b, and 1c shown in FIG. 1 at the boundary between the region 1a that becomes the bottom and the region 1b that becomes the vertical wall, the region 1b that becomes the vertical wall, and the corner portion. Preliminary mold 2 for forming a crease {see FIG. 3B to be described later in detail} at the position for dividing the region 1c to be a corner portion and the region 1c to be a corner portion into substantially equal divisions (two divisions). It is. In FIG. 2, 2a is a region of the preforming mold 2 corresponding to the region 1a to be the bottom portion, 2b is a region of the preforming mold 2 corresponding to the region 1b to be the vertical wall, and 2c is a region 1c to be the corner portion. This is the area of the corresponding preform 2.

  Fig.3 (a) is the A section enlarged view of the blank material 1 before the preforming shown in FIG. Moreover, FIG.3 (b) uses the preforming metal mold 2 shown in FIG. 2, and becomes the boundary of the area | region 1b used as the area | region 1b used as the bottom and the area | region 1b used as the bottom in the blank 1 shown in FIG. Blanks after forming creases 1d, 1e, and 1f (preliminary forming step) at the boundary between 1b and the region 1c that becomes the corner portion, and the position for dividing the region 1c that becomes the corner portion into approximately equal divisions (two divisions). FIG. 3 is a perspective view of part A of the material 1.

  FIG. 4 is a schematic perspective view showing a positional relationship among the punch 3 at the time of the main molding, the blank material 1 after the preliminary molding, and the die 4 according to the first embodiment.

  In FIG. 4, the blank 4 in which the creases 1d, 1e and 1f are formed by the above-described preforming process is made to correspond to the shape of the blank 1 and a die 4 {see FIG. 5 (b) below for details} and punch 3 {Refer to FIG. 5 (a) below for details} and press molding to form a square cylindrical part as a bottomed cylindrical part (main molding step). In this final forming step, it is not necessary to use a blank holder.

  The die 4 shown in FIG. 4 is provided with a bottom surface 4a, an inner surface 4b, and a corner portion 4c corresponding to a region 1a that becomes the bottom of the blank 1, a region 1b that becomes a vertical wall, and a region 1c that becomes a corner portion, respectively. Yes. Further, at the corner portion 4c of the die 4, one rib 1g {see FIG. 6 (d) to be described later} is formed to project outward from between the adjacent vertical walls 1b of the square tube part in a plan view during press molding. A groove 4f is provided.

  Blank material 1 in which folds 1d, 1e and 1f are formed by the above-described preforming process, detailed shape of punch 3 and die 4 shown in FIG. 5, clearance between punch 3 and die 4 {thickness of blank material 1 1 mm + (20% of blank material 1 having a thickness of 1 mm = 0.2 mm) = 1.2 mm}, lubricant (assuming cleaning oil for steel plate), and friction coefficient μ = 0.14. The deformation state of the blank 1 after the preforming was calculated using general-purpose dynamic explicit method software PAM-STAMP (the calculation result is shown as a deformation state diagram in FIG. 6). The calculation model was a 1/4 symmetry condition.

  FIG. 6 is a deformation state diagram showing the above-described calculation results. (A) is a position 70 mm upward from the bottom dead center (that is, the position where the punch 3 is at the lowermost end) (referred to as bottom dead center 70 mm UP). (B) shows bottom dead center 50 mmUP, (c) shows bottom dead center 20 mmUP, and (d) shows the deformation state of blank material 1 after preforming at bottom dead center. From this, it can be seen that the main molding process proceeds stably. In FIG. 6D, it can be seen that the rib 1g formed of a pair of folded flanges projecting outward from between the adjacent vertical walls 1b of the square tube part is well formed in the corner portion 1c. That is, it is possible to form a square tube part only by bending deformation without drawing the corner portion 1c. For this reason, even if the molding height of the square tube part is increased, the drawing resistance to the blank material 1 does not increase. In other words, the square tube part (bottomed tube without breakage) without increasing the strain amount of each part. Shaped parts) can be obtained. The rib 1g increases from the bottom 1a toward the open end of the vertical wall 1b in a side view, and extends outward from the open end of the rib 1g in a plan view. No such flange is provided.

  In the first embodiment, the example of the rib 1g that protrudes outwardly from between the adjacent vertical walls 1b of the square cylindrical part is described in the corner portion 1c, but is not limited thereto. For example, when forming one rib inwardly projecting from between the adjacent vertical walls 1b of the square tube component in the corner portion 1c, a configuration is provided in which a groove is provided in the corner portion of the outer surface of the punch 3. And it is sufficient. Further, in the first embodiment, the example in which the square tubular part is formed as the bottomed tubular part has been described, but the present invention is not limited to this. For example, it can be applied in a wide range such as a triangular cylindrical part and a pentagonal or more cylindrical part. In the first embodiment, the example in which one rib 1g projects outward from between the vertical walls 1b adjacent to each other in the plan view at the corner 1c is not limited to this. . For example, the corner portion 1c can be provided with two or more ribs projecting outward or inward from between the adjacent vertical walls 1b in plan view (see Embodiments 2 and 3 below for details). ). In Embodiment 1, an example in which a 6000 series aluminum alloy is used as the blank material 1 has been described. However, the present invention is not limited to this. For example, it is also possible to use an aluminum alloy other than 6000 series, a titanium alloy which is a difficult-to-work material, or ordinary steel. Further, the rib 1g also has an advantage of acting as a reinforcing portion against bending deformation of the corner portion 1c.

  As described above, if the configuration of the present invention is adopted, it is not necessary to perform a pair of special work on both molds (dies and punches), and a cold press capable of mass production from a blank material. Using molding, it is possible to form a bottomed cylindrical part having a high molding height only by substantially bending molding.

(Embodiment 2)
7 is a schematic plan view for explaining a blank material before being formed into a bottomed cylindrical part according to Embodiment 2 of the present invention, and FIG. 8 is a partially enlarged perspective view of a preforming mold according to Embodiment 2. FIG. 9 is a partially enlarged view of the blank material before and after the preforming according to the second embodiment, (a) is an enlarged view of a portion B before the preforming shown in FIG. 7, (b) is a perspective view after the preforming, FIG. 10 is a schematic perspective view showing the positional relationship between the punch at the time of the main molding according to the second embodiment, the blank material after the preliminary molding and the die, and FIG. 11 is a deformation state of the blank material during the main molding according to the second embodiment. FIG. In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, detailed description thereof is omitted, and only different portions are described in detail.

  In FIG. 7, the region 1 c that becomes the corner portion of the blank 1 is finished in a shape on the assumption that two ribs are formed. That is, after the main molding (press molding), the blank material 1 is finished in a shape in which the vertical wall 1b and the two ribs have the same height in a side view (see FIG. 9A).

  8 shows a blank 1 having the regions 1a, 1b, and 1c shown in FIG. 7 at the boundary between the region 1a that becomes the bottom and the region 1b that becomes the vertical wall, the region 1b that becomes the vertical wall, and the corner portion. A preforming mold 5 for forming a crease {see FIG. 9 (b) for details} at the position for dividing the region 1c to be a corner and the region 1c to be a corner portion into substantially equal divisions (four divisions). is there. In FIG. 8, 5a is a region of the preforming mold 5 corresponding to the region 1a to be the bottom portion, 5b is a region of the preforming mold 5 corresponding to the region 1b to be the vertical wall, and 5c is a region 1c to be the corner portion. This is the area of the corresponding preforming mold 5.

  FIG. 10 is a schematic perspective view showing the positional relationship among the punch 3 at the time of main molding, the blank material 1 after preforming, and the die 4 according to the second embodiment.

  In FIG. 10, the blank material 1 in which the creases 1d, 1e and the three 1f are formed by the above-described preforming process is set between the die 4 and the punch 3 so as to correspond to the shape of the blank material 1, and the press By forming, a square cylindrical part as a bottomed cylindrical part is formed (main forming step). In this final forming step, it is not necessary to use a blank holder.

  In the corner portion 4c of the die 4 shown in FIG. 10, two ribs 1g projecting outward from between the adjacent vertical walls 1b of the square tube part in a plan view during press molding {see FIG. 11 (d) below} There are provided two grooves 4f when the is formed.

  Blank material 1 in which folds 1d, 1e and three 1f are formed by the preforming process described above, the clearance between punch 3 and die 4 shown in FIG. 10, the clearance between punch 3 and die 4 {thickness of blank material 1 1 mm + (20% of blank material 1 having a thickness of 1 mm = 0.2 mm) = 1.2 mm}, lubricant (assuming cleaning oil for steel plate), and friction coefficient μ = 0.14. The deformation state of the blank 1 after the preforming was calculated using general-purpose dynamic explicit method software PAM-STAMP (the calculation result is shown as a deformation state diagram in FIG. 11). The calculation model was a 1/4 symmetry condition.

  FIG. 11 is a deformation state diagram showing the above-described calculation results. (A) is bottom dead center 70 mmUP, (b) is bottom dead center 50 mmUP, (c) is bottom dead center 20 mmUP, and (d) is bottom dead center. The deformation | transformation state of the blank material 1 after preforming in is shown, respectively. From this, it can be seen that the main molding process proceeds stably. In FIG. 11 (d), it can be seen that two corners 1 c are satisfactorily formed with two ribs 1 g formed of a pair of folded flanges projecting outward from between the adjacent vertical walls 1 b of the square tube part. . That is, it is possible to form a square tube part only by bending deformation without drawing the corner portion 1c. For this reason, even if the molding height of the square tube part is increased, the drawing resistance to the blank material 1 does not increase. In other words, the square tube part (bottomed tube without breakage) without increasing the strain amount of each part. Shaped parts) can be obtained. However, in the case of the second embodiment, since the plurality of ribs 1g are provided for the mold (punch 3 and die 4) having a very small corner R in plan view, in the groove 4f of the corner portion 4c of the die 4, The clearance between the punch 3 and the die 4 is wide. For this reason, there exists a problem that the shape of the rib 1g after press molding is not formed as sharply as the shape of Embodiment 1. FIG. When it is desired to form such ribs 1g more sharply, it is necessary to set the corner R slightly larger according to the number of ribs 1g as in the third embodiment described later. Further, these two ribs 1g are larger from the bottom 1a toward the open end side of the 1b vertical wall in a side view, and the two ribs 1g are from the open end of the rib 1g in a plan view. There is no flange extending outward.

  When the rib 1g is provided at the corner 1c as in the second embodiment, the rib 1g is formed as compared with the case where the rib 1g is provided at the corner 1c as in the first embodiment. It is possible to reduce the amount of overhang. Therefore, the number of ribs 1g provided in the corner portion 1c is preferably two or more. However, as described above, when the number of ribs 1g provided in the corner portion 1c increases, the end portion of the groove 4f facing the inside direction of the corner portion 4c of the die 4 overlaps. In such a portion, the punch 3 and the die are overlapped. Since the clearance between the four is wide, the shape of the rib 1g is not stably formed. Further, if the width of the groove 4f is narrowed so that the end portions of the groove 4f do not overlap, the volume of the portion that receives the deformation load is also reduced, and securing the strength as the die 4 becomes a problem. In order to secure the width of the groove 4f to some extent and to form the required number of relatively sharp ribs 1g, the radius of curvature R of the corner portion 4c must be set large according to the number of ribs 1g. That is, if the number of ribs 1g is too small, the amount of protrusion of the rib 1g from the corner portion 1c to the inside or outside increases, and if the number of ribs 1g is too large, the radius of curvature R of the corner portion 4c is large in plan view. turn into. Here, a rectangular tube part having a relatively small corner R (curvature radius R of about 80 mm or less) and a small protruding amount of the rib 1g to the outside or the inside of the product as desired from the viewpoint of shape restriction and securing the internal capacity. In order to obtain (bottomed cylindrical part), the number of ribs 1g provided in the corner portion 1c is preferably four or less.

  As described above, if the configuration of the present invention is adopted, it is not necessary to perform a pair of special work on both molds (dies and punches), and a cold press capable of mass production from a blank material. Using molding, it is possible to form a bottomed cylindrical part having a high molding height only by substantially bending molding.

(Embodiment 3)
12 is a schematic plan view for explaining a blank material before being formed into a bottomed cylindrical part according to Embodiment 3 of the present invention, and FIG. 13 is a partially enlarged perspective view of a preforming mold according to Embodiment 3. FIG. 14 is a partially enlarged view of the blank material before and after the preforming according to the third embodiment, (a) is an enlarged view of part C before the preforming shown in FIG. 12, (b) is a perspective view after the preforming, 15 is a schematic perspective view showing the positional relationship between the punch at the time of the main molding according to the third embodiment, the blank material after the preliminary molding, and the die, FIG. 16 is a detailed shape and dimension diagram of the punch and the die shown in FIG. These are deformation | transformation state figures which show the deformation | transformation state of the blank material in the main shaping | molding based on the Embodiment 3. FIG. In the present embodiment, the same components as those in the first and second embodiments are denoted by the same reference numerals, detailed description thereof is omitted, and only different portions are described in detail.

  In FIG. 12, the region 1 c that becomes the corner portion of the blank 1 is finished in a shape on the assumption that four ribs are formed. That is, after the main molding (press molding), the blank material 1 is finished in a shape in which the vertical wall 1b and the two ribs have the same height in a side view (see FIG. 14A).

  FIG. 13 shows the blank 1 having the regions 1a, 1b and 1c shown in FIG. 12 at the boundary between the region 1a which becomes the bottom and the region 1b which becomes the vertical wall, the region 1b which becomes the vertical wall and the corner portion. A preforming mold 6 for forming a crease {see FIG. 14 (b) for details} at the position for dividing the region 1c to be a corner and the region 1c to be a corner portion into substantially equal divisions (8 divisions). is there. In FIG. 13, 6a is a region of the preforming mold 6 corresponding to the region 1a to be the bottom portion, 6b is a region of the preforming mold 6 corresponding to the region 1b to be the vertical wall, and 6c is a region 1c to be the corner portion. This is the area of the corresponding preforming mold 6.

  FIG. 15 is a schematic perspective view showing the positional relationship between the punch 7 in the main molding according to the third embodiment, the blank material 1 after the preliminary molding, and the die 8.

  In FIG. 15, the blank material 1 in which the creases 1d, 1e and seven 1f are formed by the above-described preforming process is made to correspond to the shape of the blank material 1, and the die 8 {see FIG. 16 (b) for details) } And the punch 7 {see FIG. 16 (a) for details} and press forming a square cylindrical part as a bottomed cylindrical part (the main forming step). In this final forming step, it is not necessary to use a blank holder.

  The inside of the corner portion 8c of the die 8 shown in FIG. 16B is formed so as to have an inscribed circle radius of curvature R1 = 66.9 mm in a plan view, and this corner portion 8c is formed at the time of press molding. There are provided four grooves 8f when four ribs 1g {see FIG. 17 (e) described later} are formed to project outward from between the adjacent vertical walls 1b of the square tube part in plan view. The corner 7c on the outer surface of the punch 7 is formed in a shape having a curved surface with a radius of curvature R2 = 65.7 mm in a plan view corresponding to the inscribed circle of the corner 8c of the die 8. Here, R1> R2. The clearance between the punch 7 and the die 8 expressed by the difference between the inscribed circle radius of curvature R1 and the radius of curvature R2 is 1.2 mm. In the main forming step, the bottomed tubular part is formed only by bending without drawing, so the plate thickness change of the blank 1 is very small. For this reason, the clearance can be formed up to about 100% of the thickness of the blank 1. If the clearance is too large, the shape of the rib 1g is not sharply formed. Therefore, it can be said that it is desirable to keep the clearance at 200% or less at most. Further, as described above, the bottomed cylindrical part formed in the main forming process has very little change in the thickness of the blank 1 as a raw material as compared with a normal drawn part. That is, in the case of normal drawing, the thickness of the blank material 1 decreases near the shoulder R of the punch 7 and increases on the shoulder R side of the die 8 due to material inflow, resulting in a local decrease in the thickness. If the product performance is designed in accordance with the vicinity of the shoulder R portion, the weight of the molded part is slightly increased. In the case of the manufacturing method including the main forming step, since the change in the plate thickness of the blank material 1 accompanying the forming is small, there is an advantage that the strength and rigidity of the product can be ensured as compared with the above drawing.

  Blank material 1 in which folds 1d, 1e and seven 1f are formed by the preforming process described above, clearance between punch 7 and die 8 shown in FIG. 15, and clearance between punch 7 and die 8 {thickness of blank material 1 1 mm + (20% of blank material 1 having a thickness of 1 mm = 0.2 mm) = 1.2 mm}, lubricant (assuming cleaning oil for steel plate), and friction coefficient μ = 0.14. The deformation state of the blank 1 after the preforming was calculated using general-purpose dynamic explicit software PAM-STAMP (the calculation result is shown as a deformation state diagram in FIG. 17). The calculation model was a 1/4 symmetry condition.

  FIG. 17 is a deformation state diagram showing the above-described calculation results. (A) is bottom dead center 70 mmUP, (b) is bottom dead center 50 mmUP, (c) is bottom dead center 20 mmUP, and (d) is bottom dead center. 10 mm UP and (e) show the deformation state of the blank material 1 after preforming at the bottom dead center, respectively. From this, it can be seen that the molding process proceeds more stably than in the first and second embodiments. In FIG. 17 (e), it can be seen that four corners 1c are satisfactorily formed with four ribs 1g formed of a pair of folded flanges projecting outward from between the adjacent vertical walls 1b of the square tube part. . That is, it becomes easier to form a square tube part only by bending deformation without drawing the corner portion 1c. For this reason, even if the molding height of the square tube part is increased, the drawing resistance to the blank material 1 does not increase. In other words, the square tube part (bottomed tube without breakage) without increasing the strain amount of each part. Shaped parts) can be obtained. The four ribs 1g are larger from the bottom 1a toward the open end side of the 1b vertical wall in a side view, and the four ribs 1g are from the open end of the rib 1g in a plan view. There is no flange extending outward.

  When four ribs 1g are provided in the corner portion 1c as in the third embodiment, the protruding amount of the rib 1g is further reduced as compared with the second embodiment. In addition, the strength of the corner portion 1c is further increased in the third embodiment than in the second embodiment.

  As described above, if the configuration of the present invention is adopted, it is not necessary to perform a pair of special work on both molds (dies and punches), and a cold press capable of mass production from a blank material. Using molding, it is possible to form a bottomed cylindrical part having a high molding height only by substantially bending molding.

Further, in the main forming step of the third embodiment,
When one or more ribs 1g projecting outward from between the adjacent vertical walls 1b of the square cylindrical part (bottomed cylindrical part) in plan view are formed during press molding, the bottom surface 8a of the die 8 is formed. Provide a groove in the corner, or
When one or more ribs 1g projecting inwardly from between adjacent vertical walls 1b of a square cylindrical part (bottomed cylindrical part) are formed in a plan view during press molding, the corner of the bottom surface of the punch 7 is formed. By providing a groove in the part,
It is easier and more stable to form a square tubular part (bottomed tubular part).

  Further, the grooves provided in the corner portion 8c of the bottom surface 8a of the die 8 or the corner portion of the bottom surface of the punch 7 are formed radially from the center of each corner portion, so that the formation position of the rib 1g is further stabilized. Forming a square tube part (bottomed tubular part) is easier and more stable.

  Further, by providing a flange (not shown) extending outward from the outer surface excluding the corner portion 7c of the punch 7 on the upper end side of the punch 7, a rectangular tubular part (bottomed tubular part) is provided. It is possible to provide a flange (not shown) that extends outward from the open end of the vertical wall 1b at the same time as the press molding and without causing distortion due to bending deformation resistance to the rib 1g.

DESCRIPTION OF SYMBOLS 1 Blank material 1a The area | region 1b which becomes the bottom part of a square tube part after press molding The area | region 1c which becomes the multiple (four) vertical wall of a square tube part after press molding The corner part of several (four) square tube parts after press molding Regions 1d, 1e, 1f Creases 1g Ribs 2, 6 Preliminary mold 2a Preliminary mold 2 region 2b corresponding to region 1a Preliminary mold 2 region 2c corresponding to region 1b Region 1c Region 3 and 7 of the pre-molding die 2 Punch 4 and 8 Die 4a Bottom surface 4b of the die 4 Inner side surface 4c of the die 4 Corner 4f of the die 4 Groove 6a of the die 4 Region of the pre-molding die 6 corresponding to the region 1a 6b Region 7c of the preforming mold 6 corresponding to the region 6c region 1c of the preforming mold 6 corresponding to the region 1b Corner portion 8a of the outer surface of the punch 7 Bottom surface 8b of the die 8 Inner surface 8 of the die 8 The grooves of the corner portion 8f die 8 of the inner surface 8b of the die 8

Claims (11)

A bottomed cylindrical part having a bottom part and a plurality of vertical walls rising from the periphery of the bottom part,
This bottomed cylindrical part is formed by press-molding a blank material, and has a plurality of corner portions that are integrated with the bottom portion and the adjacent vertical wall,
The corner portion is provided with one or more ribs protruding outward or inward from between the adjacent vertical walls in plan view,
This rib consists of a pair of folded flanges folded back at the crease formed in advance in the blank material so as to divide the region to be the corner portion into approximately equal parts,
The amount of the rib protruding outward or inward increases from the bottom toward the open end of the vertical wall in a side view, and
The bottomed tubular part characterized in that the rib is not provided with a flange extending outward from an open end of the rib in a plan view.   2. The bottomed cylindrical part according to claim 1, wherein the corner portion has a substantially arc shape in a plan view, and the rib is formed at two to four locations in the corner portion having the substantially arc shape. .   The concave portion or the convex portion, which are continuous in a plan view, are formed on the bottom portion respectively corresponding to the ribs protruding outward or inward from the corner portion having the substantially arc shape. The bottomed cylindrical part described in 1.   The bottomed tubular part according to claim 3, wherein the concave portion or the convex portion provided in the bottom portion is formed radially from the center of the corner portion having the substantially arc shape in a plan view.   The bottomed cylindrical part according to any one of claims 1 to 4, wherein a flange is provided so as to extend outward from an open end of the vertical wall. A manufacturing method for manufacturing the bottomed cylindrical part according to claim 1,
The area and the vertical wall that become the bottom using a preforming mold for the blank material having the areas that become the bottom, the plurality of vertical walls, and the plurality of corners of the bottomed cylindrical part after press molding A preforming step for forming a crease at a boundary of the region to be formed, a boundary between the region to be the vertical wall and the region to be the corner portion, and a position for substantially equally dividing the region to be the corner portion; ,
A main forming step of forming the bottomed cylindrical part by setting the blank material in which the crease is formed by this pre-forming step to correspond to the shape of the blank material, setting between the die and the punch, and press forming; Have
In this final molding process,
When one or more ribs projecting outward from between the adjacent vertical walls of the bottomed cylindrical part in a plan view are formed during press molding, grooves are provided in corners of the die. And
When one or more ribs projecting inward from between the adjacent vertical walls of the bottomed cylindrical part in a plan view are formed during press molding, grooves are formed in corner portions of the outer surface of the punch. A method for manufacturing a bottomed tubular part, characterized in that the structure is provided.   The bottomed cylindrical shape according to claim 6, wherein the number of positions for forming folds in order to divide the region to be the corner portion into substantially equal parts in the preforming step is 3 to 7. A manufacturing method for parts. The inside of the corner portion of the die is formed so as to have an inscribed circle radius of curvature R1 in plan view, and the corner portion of the outer surface of the punch is a plane corresponding to the inscribed circle of the corner portion of the die. The clearance between the punch and the die represented by R1-R2 is 100% or more and 200% of the plate thickness of the blank material. The manufacturing method of a bottomed cylindrical part according to claim 6 or 7, wherein the manufacturing method is set as follows.
Here, R1> R2. In the main forming step,
When one or more ribs projecting outward from between the adjacent vertical walls of the bottomed cylindrical part in a plan view are formed during press molding, grooves are provided in corner portions of the bottom surface of the die. And
When one or more ribs projecting inward from between the adjacent vertical walls of the bottomed cylindrical part in plan view are formed during press molding, a groove is provided in a corner portion of the bottom surface of the punch. The method for manufacturing a bottomed cylindrical part according to claim 8, wherein:   The bottomed cylindrical shape according to claim 9, wherein the grooves respectively provided in the corner portion of the bottom surface of the die or the corner portion of the bottom surface of the punch are formed radially from the center of each corner portion. A manufacturing method for parts.   The existence according to any one of claims 6 to 10, wherein a flange is provided on an upper end side of the punch so as to extend outward from an outer surface excluding a corner portion of the punch. Manufacturing method of bottom cylindrical parts.

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