JP5077211B2 - Molded body having odd-shaped U-shaped portion and manufacturing method thereof - Google Patents

Description

  The present invention relates to a method of manufacturing a molded body having a deformed U-shaped portion that has a concave curved surface bent so that a bottom surface portion is recessed inward along a longitudinal direction.

  For example, a frame component incorporated in a seat back of a vehicle seat has a rectangular cross section, and two surfaces corresponding to the long side portion (hereinafter, referred to as a long side surface as appropriate) are substantially flat. Although there is a surface, there is a component having a shape in which a surface corresponding to the short side portion (hereinafter, referred to as a short side surface as appropriate) is curved along the shape of the seat back. One short side surface is curved to be convex outward along the longitudinal direction, and the other short side surface is convex inward along the longitudinal direction (indented inward) It is curved.

  Such a specially shaped member is difficult to manufacture as a single part from a single material. For this reason, conventionally, two parts having a short side surface erected from both curved end portions of a substantially flat long side surface are formed, and these short side surfaces are welded together to form a rectangular cross section. Was manufactured by doing.

Japanese Patent Publication No. 6-61581 JP 2002-1445 A Japanese Patent No. 2855492

However, in the manufacturing method in which two parts are formed and bonded as described above, the number of manufacturing steps is large and the material yield is not good. Furthermore, since the welding is performed at two locations in the finished product, it is disadvantageous in strength, and it is difficult to reduce the weight by increasing the weight of the welded portion.
In order to solve such a problem, it is necessary to find a method that can be manufactured with one component from one material to the end and that can reduce the number of parts to be welded.

In order to establish such a manufacturing method, it is considered indispensable to produce a molded article having a U-shaped cross section with the short side surface as the bottom.
However, it is very difficult to form a molded body having a so-called deformed U-shaped portion with the curved surface as described above as the bottom surface portion. In a simple molding method, processing such as so-called stretch flange molding is required, and a large warp and an unnecessary wrinkle-like appearance defect occur on the side surface, making it difficult to produce a product. It is difficult to solve even if the above three documents are considered.
In addition, products having such an irregular U-shaped portion are not limited to the frame components incorporated in the seat back described above, but also exist in machine components for various applications.
Therefore, it is very effective if a method for easily producing a molded body having the odd-shaped U-shaped portion is completed.

  The present invention has been made in view of such conventional problems, and a molded body having a deformed U-shaped portion having a concave curved surface bent so that a bottom surface portion is recessed inward along the longitudinal direction has an appearance characteristic. The present invention is intended to provide a method capable of producing a single component from a single material with a high yield.

1st invention exhibited the cross-sectional U-shape which has a bottom face part and a pair of left and right side parts erected from both sides of the bottom face part, and the bottom face part was bent so as to be recessed inward along the longitudinal direction. A method for producing a molded body having a deformed U-shaped portion having a concave curved surface,
Prepare a flat blank,
The blank material is bent starting from a linear boundary line between the bottom surface portion and the side surface portion, and the bottom surface portion is a flat surface and the angle formed between the side surface portions on both sides thereof is Both form an intermediate molded body that is obtuse,
Corresponding to the punch having a concave clamping surface corresponding to the desired inner surface shape of the concave curved surface in the bottom surface portion, the cushion having the convex clamping surface corresponding to the outer surface shape of the concave curved surface, and the outer width dimension of the bottom surface portion Using a die having a die having a die blade portion arranged at an interval of the punch, the concave sandwiching surface of the punch disposed inside the intermediate molded body and the cushion disposed opposite thereto The bottom surface portion is sandwiched by the convex sandwiching surface to deform the bottom surface portion into the concave curved surface,
Then, while maintaining the clamping state between the punch and the cushion, the entire bottom surface portion is inserted between the die blade portions, and when only a part of the side surface portion passes through the die blade portion, By stopping the relative movement between the bottom surface portion and the die, a part of the side surface portion that does not pass between the die blade portions becomes a bulging portion that bulges outward, and its periphery is In the method for producing a molded body having a deformed U-shaped portion, the deformed U-shaped portion is formed so as to be a planar side surface portion erected substantially perpendicular to the bottom surface portion (claim) Item 1).

  In the production method of the present invention, as described above, the intermediate molded body is once formed using a flat blank. Since this intermediate molded body has a shape in which the bottom surface portion is a flat surface and the angle between the side surface portions on both sides thereof is an obtuse angle, it can be easily obtained by simple bending.

  Next, the intermediate molded body is processed by the mold. First, the bottom surface portion is sandwiched by the concave sandwiching surface of the punch and the convex sandwiching surface of the cushion to deform the bottom surface portion into the concave curved surface. When the deformation of the bottom surface portion is executed, a stronger tensile stress is applied to the side surface portions on both sides of the bottom surface portion as the distance from the bottom surface portion increases. Therefore, it deform | transforms so that it may open between side parts, and a part of side part will swell and will be in the state which is not flat. In addition, since the deformation | transformation at this time also has the ratio of elastic deformation, if the clamping state of the said punch and the said cushion is cancelled | released, it will approximate the shape of the original intermediate molded object. Therefore, the next step is performed while maintaining the sandwiched state between the punch and the cushion.

Specifically, it is inserted between the die blades with the entire bottom surface being at the top while maintaining the clamping state between the punch and the cushion. That is, the boundary line portion between the bottom surface portion and the side surface portion is all passed between the die blade portions. Thereby, the corner | angular part between the said bottom face part and the said side part becomes a substantially right angle.
And the relative advance with respect to the die | dye of the said intermediate molded object is stopped when only a part of said side part passes the said die blade part after the said whole bottom face part passed the die blade part. And it avoids that the whole side part passes a die blade part. As a result, the bottom surface portion and the pair of left and right side surfaces standing from both sides thereof have a U-shaped cross section, and the bottom surface portion exhibits a concave curved surface that is bent inward along the longitudinal direction. A molded body having a deformed U-shaped portion can be obtained.

  The odd-shaped U-shaped part of the molded body thus obtained is inevitably the bulging part partially bulging outward, not the entire side part. Due to the presence of the bulging portion, the rigidity of the side surface portion can be increased. On the other hand, the above manufacturing method cannot be applied to products in which the shape of the bulging portion is not allowed.

In addition, the bulging portion formed on the side surface portion is formed with a very smooth natural shape change in the surrounding flat side surface portion, and the appearance characteristics such as unnecessary wrinkles are reduced. Does not occur. Rather, it can be regarded as a shape in which the above-mentioned bulging portion is positively provided, and an excellent appearance characteristic that brings out even a novel design can be obtained.
On the other hand, when the intermediate formed body is passed between the die blade portions, when the entire side surface portion is passed, the so-called springback phenomenon occurs after the entire shape becomes substantially flat and is taken out between the dies. As a result, a phenomenon occurs in which the distance between both side surfaces increases as the distance from the bottom surface increases. Furthermore, wrinkle-like appearance defects remain on the side portions, making it difficult to produce a product.

  Thus, by using the manufacturing method of the present invention, as described above, a molded body having a deformed U-shaped portion that has a concave curved surface that is curved so that the bottom surface portion is recessed inward along the longitudinal direction has an appearance characteristic. It can be easily manufactured in an excellent state, and can be manufactured from a single material with a high yield as a single component. And since the said odd-shaped U-shaped part of the obtained molded object becomes what integrally connected the bottom face part and the side part on the both sides, it is not necessary to join by welding. Therefore, the weight can be reduced accordingly. Furthermore, the plate | board thickness of raw material itself can also be reduced by the strength improvement effect by the rigidity improvement of the said side part, and the necessity of a welding part, and the weight reduction effect by this can also be acquired.

Next, the second invention presents a U-shaped cross section having a bottom surface portion and a pair of left and right side surface portions erected from both sides of the bottom surface portion, and the bottom surface portion is recessed inward along the longitudinal direction. A molded body having a deformed U-shaped portion that has a concavely curved curved surface,
The side surface portion has a bulging portion that bulges outward, and has a flat side surface portion erected substantially perpendicular to the bottom surface portion around the bulging portion. It exists in the molded object which has a character-shaped part (Claim 5).

The molded body of the present invention can be obtained, for example, by the above-described manufacturing method. As described above, the side surface portion has the bulged portion, so that the side surface portion has excellent rigidity and strength. . Further, the bulging portion formed on the side surface portion is formed with a very smooth natural shape change in the surrounding flat side surface portion, and the appearance characteristics such as unnecessary wrinkles are reduced. No, it has excellent appearance characteristics that create a novel design.
Further, the odd-shaped U-shaped portion is configured such that the bottom surface portion and the side surface portions on both sides thereof are integrally connected, and is not joined by welding. For this reason, it is possible to improve the strength of the bottom surface portion by not performing welding. Moreover, these strength improvement parts can also be connected to the thinning of a raw material, and it is also possible to reduce in weight.

In the manufacturing method of this invention, it is preferable that the said die blade part of the said die | dye is provided on two parallel straight lines (Claim 2). In this case, the side surface portion in the vicinity of both ends in the longitudinal direction of the curved bottom portion passes through the die blade portion to a relatively deep position, and the vicinity of the central portion is formed to pass the die blade portion only to a relatively shallow position. can do. Thereby, it becomes possible to set the formation position of the said bulging part from the center.
It is also possible to adjust the position and shape of the bulging portion by providing the die blade portion of the die in a curved shape.

  The intermediate molded body preferably has an angle formed by the bottom surface portion and the side surface portion in a range of 135 ° ± 10 °. In this case, it is possible to facilitate deformation when the bottom portion of the intermediate molded body is sandwiched between the punch and the cushion. On the other hand, when the angle formed between the bottom surface portion and the side surface portion is less than 125 ° or exceeding 145 °, subsequent molding is possible, but the deformation at the time of clamping may not be stabilized.

  Further, the bending process for forming the intermediate molded body corresponds to a pre-processed die having a valley-shaped molding surface corresponding to the bent shape of the bottom surface part and the side surface part of the intermediate molded body, and the bent shape. It is preferable to carry out by sandwiching the blank material between them using a pre-processed punch having a chevron-shaped molding surface (Claim 4). In this case, it is possible to easily form the intermediate molded body simply by sandwiching the blank material with the preliminary processing die and the preliminary processing punch.

  Next, in the molded body, at least one of the pair of left and right side surfaces is molded and joined to each other so that end portions on the opposite side to the bottom surface are close to each other, and the cross-sectional shape is the U-shape. It can also be set as the structure used as the closed cross-sectional shape containing a shape (Claim 6). In this case, it is not necessary to weld at least the bottom surface portion of the odd-shaped U-shaped portion, and high strength and light weight can be achieved.

  Moreover, the said molded object is applicable to the frame components incorporated in the seat back of a vehicle seat (Claim 7). In this case, it is possible to increase the strength and weight as described above, and it is optimal as a frame component built in the seat back of the vehicle seat.

Example 1
A molded body having a deformed U-shaped portion according to an embodiment of the present invention and a manufacturing method thereof will be described with reference to FIGS.
As shown in FIGS. 1 to 3, the molded body 1 manufactured in this example has a U-shaped cross section having a bottom surface portion 21 and a pair of left and right side surface portions 22 and 23 erected from both sides of the bottom surface portion 21. It is a molded body having a deformed U-shaped portion 20 which is formed and presents a concave curved surface in which the bottom surface portion 21 is bent inward along the longitudinal direction. The side surface portions 22 and 23 have bulging portions 225 and 235 that bulge outward, and the planar side surface portions erected substantially perpendicular to the bottom surface portion 21 around the bulging portions 225 and 235. 226, 236.

In producing the molded body 1, first, as shown in FIG. 4, a blank 10 made of a flat steel plate is prepared. In this example, the width dimension of the blank material 10 is changed to correspond to the width dimension of the side surface portions 22 and 23, and a substantially trapezoidal shape is obtained. Further, the blank 10 was provided with a plurality of through holes 19 for weight reduction in advance.
Next, as shown in FIGS. 5 and 6, an intermediate molded body 15 is formed using the blank material 10.

  In this example, as shown in FIG. 5, bending is performed using a pair of preforming molds 4. The preforming die 4 corresponds to a pre-processing die 41 having a valley forming surface 410 corresponding to the bent shape of the bottom surface portion 21 and the side surface portions 22 and 23 of the intermediate molded body 15 to be obtained, and the bent shape. And the pre-processed punch 42 having the ridge-shaped forming surface 420.

  More specifically, the preliminary processing die 41 has the above-described valley-shaped molding surface 410 that is recessed downward from the flat upper surface 411, and the valley-shaped molding surface 410 has a cushion portion 413 having a flat receiving surface 412 on the upper surface. And a pair of tapered die surfaces 414 that are inclined so that a spatial distance between the two becomes wider toward the upper side. The cushion portion 413 is disposed so as to be retractable in accordance with the pressing force from the preliminary machining punch 42.

  The mountain-shaped forming surface 420 of the pre-processed punch 42 has a pair of tapered punch surfaces 424 that are inclined to the left and right of the flat front end surface 421 so that the thickness dimension between the two becomes wider as it approaches the upper side. A pair of corners 425 between the tip surface 421 and the taper punch surface 424 correspond to the boundary line a between the intermediate part 15 and the bottom part 21 and the side parts 22 and 23 of the intermediate part 15 to be obtained, respectively. It is provided to do. Further, the taper die surface 414 and the taper punch surface 424 of the preliminary machining die 41 are inclined according to the formation angle of the side surface portions 21 and 22 of the intermediate molded body 15 to be obtained. In this example, the inclination angle α is set to 45 ° with respect to the relative movement direction of the preliminary machining punch 42, that is, the angle between the bottom surface portion 21 and the side surface portions 22 and 23 is set to 135 °.

  Using such a preforming die 4, first, as shown in FIG. 5A, the blank material 10 is placed on the upper surface 411 of the preforming die 41. At this time, the position that becomes the boundary line a (FIG. 6) between the bottom surface portion 21 and the side surface portions 22 and 23 is matched with the position facing the corner portion 425 of the preliminary machining punch 42.

  Next, as shown in FIG. 5B, the preliminary processing punch 42 is relatively advanced toward the preliminary processing die 41 to insert the mountain-shaped forming surface 420 into the valley-shaped forming surface 410. Thereby, the blank material 10 is bent with the linear boundary line a between the bottom surface portion 21 and the side surface portions 22 and 23 as a starting point. As shown in FIG. 6, an intermediate molded body 15 is obtained in which the bottom surface portion 21 is a flat surface and the angle β between the side surface portions 22 and 23 on both sides thereof is an obtuse angle of approximately 135 °. .

  Next, as shown in FIG. 7, a punch 51 having a concave clamping surface 510 corresponding to the desired inner surface shape of the concave curved surface in the bottom surface portion 21 and a convex clamping surface 520 corresponding to the outer surface shape of the concave curved surface. Processing is performed using the mold 5 including the cushion 52 having the die 52 and the die 53 having the die blade portion 530 arranged at an interval corresponding to the outer width dimension of the bottom surface portion 21.

  The punch 51 has an insertion part 511 having a thickness corresponding to the inner dimension of the side parts 21 and 22 of the molded body 1 to be obtained, and the concave sandwiching surface 510 is provided at the tip thereof. The angle γ formed between the side surface 512 of the insertion portion 511 and the concave sandwiching surface 510 is a right angle (90 °).

The cushion 52 has the same thickness as the insertion portion 511 of the punch 51, and has the convex sandwiching surface 520 on the upper end surface.
The die 53 includes a pair of left and right die blade portions 530, and the cushion 52 is disposed therebetween. The die blade portion 530 has a cross-sectional shape set to an arc shape having a radius of curvature R of ____mm. In addition, by making the upper surface 531 of the die 53 a flat surface, the shape along the longitudinal direction of the die blade portion 530 was provided on two parallel straight lines.
The cushion 52 is arranged so that it can be raised and lowered in a state in which the convex clamping surface 520 protrudes above the die 53 in the initial state.

As shown in FIG. 8 (a), using the mold 5, the concave sandwiching surface 510 of the punch 51 disposed inside the intermediate molded body 15 and the convex sandwiching surface 520 of the cushion 52 disposed opposite thereto are used. The bottom surface portion 21 is sandwiched to deform the bottom surface portion 21 into a concave curved surface.
When the deformation of the bottom surface portion 21 is executed, a stronger tensile stress is applied to the side surface portions 22 and 23 on both sides in the longitudinal direction as the distance from the bottom surface portion 21 increases. Therefore, as shown in the figure, the side surface portions 22 and 23 are deformed so as to be opened, and a part (b portion) of the side surface portions 22 and 23 swells and is not flat. In addition, since the deformation | transformation at this time also has the ratio of elastic deformation, if the clamping state of the said punch 51 and the cushion 52 is cancelled | released, the shape of the original intermediate molded object 15 will be approached. Therefore, the next step is performed while maintaining the sandwiched state between the punch 51 and the cushion 52.

  That is, as shown in FIG. 8B, the entire bottom surface 21 is inserted between the die blades 530 while maintaining the sandwiched state between the punch 51 and the cushion 52. And the part of the boundary line a between the bottom face part 21 and the side face parts 22 and 23 is made to pass between the die blade parts 530. Thereby, the corner | angular part between the bottom face part 21 and the side part 22 and 23 becomes a substantially right angle.

  Further, as shown in the figure, relative advancement of the intermediate molded body 15 with respect to the die 53 is such that after the entire bottom surface portion 21 passes through the die blade portion 530, only a part of the side surface portions 22 and 23 is the die blade portion 530. Is stopped at the time of passing, so that the entire side portions 22 and 23 do not pass the die blade portion 530. Accordingly, the bottom surface portion 21 and the pair of left and right side surface portions 22 and 23 erected from both sides thereof have a U-shaped cross section, and the bottom surface portion 21 is a concave shape that is bent inward along the longitudinal direction. A molded body 1 having a deformed U-shaped portion 20 having a curved surface is obtained. The deformed U-shaped portion 20 of the obtained molded body 1 inevitably has the side surface portions 22 and 23 not flat surfaces, and the bulging portions 225 and 235 partially swelled outwardly. Become. Due to the presence of the bulging portions 225 and 235, the rigidity of the side surface portions 22 and 23 can be increased as compared with the case where the entire side surface portion is flat.

  Further, the bulging portions 225 and 235 formed on the side surface portions 22 and 23 are formed by a very smooth natural shape change in the surrounding planar side surface portions 226 and 236, and unnecessary wrinkles and the like are formed. Features that reduce appearance characteristics do not occur. Rather, it can be regarded as a shape in which the bulging portions 225 and 235 are actively provided, and an excellent appearance characteristic having a novel design can be obtained. Further, the presence of the through holes 19 provided in the blank 10 in advance did not cause any problem in molding, and the above-described excellent appearance characteristics were not deteriorated.

Moreover, if the manufacturing method of this example is used, the molded object 1 which has the odd-shaped U-shaped part 20 which exhibits the concave curved surface curved so that the bottom face part 21 may be depressed inward along a longitudinal direction as mentioned above is an external appearance characteristic. Can be easily manufactured in a superior state, and can be manufactured with a high yield as a single component from a single material.
As shown in FIG. 9, when the blank material 10 is sampled from the strip-shaped steel plate, the yield 109 is improved as a result of the comparison of the later-described comparative material and the conventional material into two parts. It can be easily understood because it can be less than the case.

  Further, since the odd-shaped U-shaped portion 20 of the obtained molded body 1 is obtained by integrally connecting the bottom surface portion 21 and the side surface portions 22 and 23 on both sides thereof, it is not necessary to perform joining by welding. Therefore, the weight can be reduced accordingly. Furthermore, the plate | board thickness of raw material itself can also be reduced by the strength improvement effect by the rigidity improvement of the said side parts 22 and 23, and the necessity of a welding part, and the weight reduction effect by this can also be acquired.

(Comparative Example 1)
In this example, as shown in FIG. 10B, the bulging portions 225 and 235 are not provided, and the entire surface has flat side portions 922 and 923, and the bottom portion 921 is along the longitudinal direction as in the first embodiment. An attempt was made to produce a molded body 9 having a concave curved surface bent so as to be recessed inward. The mold used for molding is the same as the mold 5 of the first embodiment.

  First, as shown in FIG. 10A, a blank 10 is prepared, and a flat blank 10 is formed by a concave sandwiching surface 510 of a punch 51 and a convex sandwiching surface 520 of a cushion 52 in which the blank 51 is opposed to this. The entire blank material 10 is deformed into a concave curved surface by sandwiching a portion to be 921.

  Next, as shown in FIG. 10B, the blank material 10 is inserted between the die blade portions 530 with the entire portion that becomes the bottom surface portion 921 being maintained, while maintaining the sandwiched state between the punch 51 and the cushion 52, and the side surface at a stretch. The entire portions 922 and 923 are passed between the die blade portions 530. Thereby, the molded body 9 in which the corners between the bottom surface portion 921 and the side surface portions 922 and 923 are substantially perpendicular is obtained.

  Next, as shown in FIG. 10C, the punch 51 and the cushion 52 are raised and the molded body 9 is extracted from the die 53. As a result, as shown in FIG. 11, the obtained molded body 9 was deformed so that the side surface portions 921 and 922 spread away from the bottom surface portion 921, and a desired U-shaped portion was not obtained. Further, the side portions 921 and 922 were not formed with the bulging portions 225 and 235 as in the case of the first embodiment, and were in a flat state as a whole, but a large number of wrinkle-like appearance defects were formed. The product was difficult to commercialize due to the poor appearance.

(Example 2)
In this example, a molded body 102 as a frame part built in a seat back of a vehicle seat was manufactured using the molded body 1 obtained in Example 1. The molded body 102 is molded such that the end portions 227 and 237 on the opposite side to the bottom surface portion 21 of the pair of left and right side surface portions 22 and 23 in the molded body 1 in the first embodiment are joined to each other. . The cross-sectional shape of the molded body 102 is a substantially rectangular closed cross-sectional shape including the U-shape.

That is, the end portions 227 and 237 of the side surface portions 22 and 23 are both bent inward at substantially right angles. In this bending process, a mold member (not shown) having a corner corresponding to a desired bending angle is inserted between the side portions 22 and 23 and the end portions 227 and 237 of the side portions 22 and 23 are pressed from the outside. Can be done. This bending process can be performed by various known methods.
The end portions 227 and 237 of the side surface portions 22 and 23 are partially overlapped and joined by welding.

  In the frame part formed of the molded body 102 having the above-described configuration, the welded portion is only the contact portion of the end portions 227 and 237. That is, only one of the two short side surfaces in the rectangular cross section is welded, and the other bottom surface 21 is integrated from the beginning. Thereby, compared with the structure comprised from the material of the conventional 2 sheets, and both the two short side part surfaces were joined by welding, it becomes the thing excellent in the strength surface and the weight surface.

(Comparative Example 2)
In this comparative example, a molded body 902 (FIG. 15) as a frame component incorporated in the seat back of a vehicle seat similar to that in the second embodiment is changed from one material to a first material by a method different from that in the first and second embodiments. It is an example which manufactures with components.

In this comparative example, as shown in FIG. 13, a substantially V-shaped blank 90 is used as a material. And as shown in FIG. 14, the both-sides edge part of the outer side of the V-shape of the blank material 90, and an inner edge part are turned up at right angle, and the short side part surfaces 931-934 are formed.
Next, as shown in FIGS. 14 and 15, bending is performed starting from the boundary line c, the short side surface 931 and the short side surface 932 are brought into contact, and the short side surface 933 and the short side portion are brought into contact with each other. The surface 934 is brought into contact. Then, the molded object 902 which has the cross section of a substantially rectangular cross section is obtained by welding the contact part of each short side part surface.

  The obtained molded body 902 has a substantially straight flat surface portion 939 in a different direction from the bottom surface portion 21 of Example 2, that is, a short side surface portion that has a curved surface that protrudes outward along the longitudinal direction. The structure is integrated from the beginning, and bending is performed starting from the boundary line c on both sides. Thereby, processing can be completed without performing so-called stretch flange processing.

  However, the molded body 902 has a welded portion that is approximately 1.5 times as long as the second embodiment. Accordingly, it is inferior to the molded body 102 of Example 2 in terms of weight and strength. Furthermore, as shown in FIG. 13, the remaining scrap portion obtained by removing the blank material 90 from the belt-shaped steel plate increases as compared with the case of Example 2 (Example 1), and the yield also decreases.

The perspective view which shows the molded object in the state which stood up the odd-shaped U-shaped part in Example 1. FIG. The perspective view which shows the molded object in the state which laid the deformed U-shaped part in Example 1. FIG. Sectional drawing in Example 1 (AA arrow directional cross-sectional view of FIG. 1). The top view which shows the blank material in Example 1. FIG. In Example 1, (a) a state in which the blank material is disposed between the preliminary processing die and the preliminary processing punch, and (b) immediately after the blank material is sandwiched between the preliminary processing die and the preliminary processing punch and bent. Explanatory drawing which shows the state of. 2 is a perspective view of intermediate molding in Example 1. FIG. Explanatory drawing which shows the structure of the metal mold | die provided with the punch, cushion, and die in Example 1. FIG. In Example 1, (a) The state which pinched | interposed the blank material between the punch and the cushion, (b) The explanatory view which shows the state which made the whole bottom face part and only a part of side part pass between die blade parts. Explanatory drawing which shows the method of extract | collecting a blank material from a strip | belt-shaped steel plate in Example 1. FIG. In Comparative Example 1, (a) a state in which a blank material is sandwiched between the punch and the cushion, (b) a state in which the entire bottom surface portion and the entire side surface portion are passed between the die blade portions, and (c) the molded body is dies. Explanatory drawing which shows the state taken out from. The perspective view of the molded object in the comparative example 1. FIG. The perspective view of the molded object in Example 2. FIG. Explanatory drawing which shows the method in which the blank material is extract | collected from the strip | belt-shaped steel plate in the comparative example 2. FIG. Explanatory drawing which shows the state which performed the bending process in the blank material in the comparative example 2. FIG. The perspective view of the molded object in the comparative example 2. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,102,9,902 Forming body 20 Profile-shaped U-shaped part 21 Bottom face part 22, 23 Side face part 225, 235 Swelling part 226, 236 Planar side face part 4 Pre-molding die 41 Pre-processing die 410 Valley-shaped forming surface 42 Pre-processed punch 420 Cone forming surface 5 Die 51 Punch 510 Concave pinching surface 52 Cushion 520 Convex pinching surface 53 Die 530 Die blade part

Claims (7)

It has a U-shaped cross section having a bottom surface portion and a pair of left and right side portions erected from both sides of the bottom surface portion, and has a concave curved surface that is curved so as to be recessed inward along the longitudinal direction. A method for producing a molded body having an irregular U-shaped part,
Prepare a flat blank,
The blank material is bent starting from a linear boundary line between the bottom surface portion and the side surface portion, and the bottom surface portion is a flat surface and the angle formed between the side surface portions on both sides thereof is Both form an intermediate molded body that is obtuse,
Corresponding to the punch having a concave clamping surface corresponding to the desired inner surface shape of the concave curved surface in the bottom surface portion, the cushion having the convex clamping surface corresponding to the outer surface shape of the concave curved surface, and the outer width dimension of the bottom surface portion Using a die having a die having a die blade portion arranged at an interval of the punch, the concave sandwiching surface of the punch disposed inside the intermediate molded body and the cushion disposed opposite thereto The bottom surface portion is sandwiched by the convex sandwiching surface to deform the bottom surface portion into the concave curved surface,
Then, while maintaining the clamping state between the punch and the cushion, the entire bottom surface portion is inserted between the die blade portions, and when only a part of the side surface portion passes through the die blade portion, By stopping the relative movement between the bottom surface portion and the die, a part of the side surface portion that does not pass between the die blade portions becomes a bulging portion that bulges outward, and its periphery is The method for producing a molded body having a deformed U-shaped portion, wherein the deformed U-shaped portion is formed so as to be a planar side surface portion erected substantially perpendicular to the bottom surface portion.   2. The method for manufacturing a molded body having a deformed U-shaped portion according to claim 1, wherein the die blade portion of the die is provided on two parallel straight lines.   3. The production of a molded body having an odd-shaped U-shaped portion according to claim 1 or 2, wherein the intermediate molded body has an angle formed by the bottom surface portion and the side surface portion in a range of 135 ° ± 10 °. Method.   The bending process for forming the intermediate molded body according to any one of claims 1 to 3 has a valley-shaped molding surface corresponding to a bent shape of the bottom surface portion and the side surface portion of the intermediate molded body. Forming with a deformed U-shaped portion characterized in that it is performed by sandwiching the blank material between a pre-processed die and a pre-processed punch having a mountain-shaped forming surface corresponding to the bent shape. Body manufacturing method. It has a U-shaped cross section having a bottom surface portion and a pair of left and right side portions erected from both sides of the bottom surface portion, and has a concave curved surface that is curved so as to be recessed inward along the longitudinal direction. A molded body having a modified U-shaped part,
The side surface portion has a bulging portion that bulges outward, and has a flat side surface portion erected substantially perpendicular to the bottom surface portion around the bulging portion. Molded body having a letter-shaped part.   6. The pair of left and right side portions according to claim 5, wherein at least one of the pair of left and right side portions is molded and joined to each other so that ends opposite to the bottom portion are close to each other, and the cross-sectional shape includes the U-shape. A molded article having a modified U-shaped portion characterized by having a closed cross-sectional shape.   The molded body according to claim 6, wherein the molded body is a frame component built in a seat back of a vehicle seat.

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