Press molding method of t-shaped press component and t-shaped press molding component

Abstract

To increase a length of a press molding surface at a plate-like portion in a second component forming part to prevent or inhibit occurrence of wrinkles in the second component forming part in a first press molding step.SOLUTION: A press molding method of a T-shaped press molding component, such as a center pillar 10, includes a first press molding step and a second press molding step to perform molding. In the first press molding step, a specific area range Y of a second component forming part B in an area where a first component forming part A extends from an end of the first component forming part A in the T shaped press molding component X in a second component forming part B direction is press-molded as a protruding shape having a height that protrudes to the upper side relative to a height position of a top plate part 24 of the first component forming part A.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present invention relates to a press-molding method for a T-shaped press part and a T-shaped press-molded part. In particular, the present invention is directed to a T-shaped press-molded part that is a member for forming an upper portion of a center pillar that forms the side frame of an automobile. [Background technology]

[0002] T-shaped press-formed parts are used as components that form the framework of vehicles such as automobiles. For example, the upper part of the center pillar that forms the side framework of an automobile is a T-shaped press-formed part.

[0003] The T-shaped press-molded part of the upper position forming member of the center pillar is usually arranged in the side frame of the automobile in the following form: That is, the T-shaped press-molded part is arranged by integrally connecting a first part forming part arranged in the vertical direction (height direction of the vehicle) and a second part forming part arranged in the horizontal direction (front-rear direction of the vehicle) into a T shape.

[0004] The first component forming portion is a member having a hat-shaped cross section formed of a top plate portion, a side plate portion, and a flange portion, and is disposed in the vehicle height direction (vertical direction) and is disposed as an elongated shape. In this case, the top plate portion of the hat-shaped cross section is disposed at an outer position in the vehicle width direction.

[0005] The second part forming part is a member arranged in a flat shape at an end of the first part forming part having an elongated shape in a direction intersecting with the first part forming part. The second part forming part is formed integrally and continuously with the first part forming part, but the position where the flat shape of the second part forming part is formed is a position protruding from the position of the top plate part of the hat-shaped cross section of the first part forming part.

[0006] In other words, the arrangement of the first part forming part and the second part forming part at the connection position of both forming parts is such that the position of the flat form of the second part forming part protrudes outward in the width direction, when viewed in the vehicle width direction, from the position of the top plate portion of the hat-shaped cross-sectional shape of the first part forming part.

[0007] The above-mentioned T-shaped press-molded parts are usually press-molded by a drawing process in the first press-molding process and a bending process or pad drawing (grasping bending) process in the second press-molding process. In this press-molding process, wrinkles may occur on the press-molded surface of the T-shaped press-molded parts due to press-molding. For this reason, a molding method has been proposed in which a convex shape (a small mound of excess material) is formed in the region near the connection part of the first part-forming part with the second part-forming part in the drawing process of the first press-molding process (see Patent Document 1 below). This increases the line length of the press-processed surface in the drawing process of the first press-molding process, preventing or suppressing the occurrence of wrinkles. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] JP 2019-13952 A Summary of the Invention [Problem to be solved by the invention]

[0009] However, in the above-mentioned drawing of the first part forming part, there is a problem that wrinkles occur in the flat plate-shaped portion of the second part forming part during the drawing process of the first press forming step. The inventors noticed that this is due to the difference in line length of the press-formed surface in the cross section in the vehicle front-rear direction of the first part forming part and the second part forming part. The inventors also noted that if wrinkles occur, the product quality cannot be satisfied.

[0010] The present invention has been devised in view of the above-mentioned points, and the problem that the present invention aims to solve is to prevent or suppress the occurrence of wrinkles in the second part forming portion by increasing the length of the press-molded surface of the flat portion of the second part forming portion in the first press molding process. [Means for solving the problem]

[0011] In order to solve the above problems, the press-molding method for a T-shaped press part and the T-shaped press-molded part according to the present invention take the following measures.

[0012] A first aspect of the present invention is a press molding method for a T-shaped press part, the press molding method including at least a first press molding step and a second press molding step, the first press molding step comprising: a first part forming part formed by arranging a hat-shaped cross-sectional shape having a top plate portion, a side plate portion, and a flange portion in a long shape; and a second part forming part arranged in a flat plate shape at an end of the first part forming part in a direction intersecting the first part forming part and formed integrally with the first part forming part, the flat plate shape being formed at a position protruding from the position of the top plate portion of the hat cross-sectional shape in the first part forming part. The first press molding step is a press molding method for a T-shaped press part, the first press molding step being a step of pressing a specific region of the second part forming part in an area obtained by extending the first part forming part from the end of the first part forming part in the T-shaped press part toward the second part forming part, into a convex shape having a height protruding above the height position of the top plate portion of the first part forming part.

[0013] A second invention of the present invention is a press molding method for a T-shaped press part of the first invention described above, wherein in the first press molding process, the forming height of the convex shape set in a specific area range of the second part forming part is lower than the forming height of the flat shape of the second part forming part press molded in the second press molding process.

[0014] A third invention of the present invention is a press molding method for a T-shaped press part of the second invention described above, wherein in the press molding of the second press molding process, an additional convex shape is set at the position of an ascending slope of a connection part from an end part of the first part forming part to the second part forming part, and press molding is performed.

[0015] A fourth invention of the present invention is a press molding method for a T-shaped press part of the third invention described above, wherein additional convex shape forms set at the ascending slope position of the connection portion from the end of the first part forming part to the second part forming part are positions on both sides of the top plate of the first part forming part at the position of the connection portion.

[0016] A fifth aspect of the present invention is a press molding method for a T-shaped press part of any one of the first to fourth aspects described above, wherein the T-shaped press part is an upper portion forming member of a center pillar that forms the side frame of an automobile.

[0017] A sixth aspect of the present invention is a T-shaped press-molded part having a first part forming part formed by arranging a hat-shaped cross-sectional shape having a top plate portion, a side plate portion and a flange portion in a long shape, and a second part forming part arranged in a flat plate form at an end of the first part forming part in a direction intersecting the first part forming part and formed integrally with the first part forming part, the flat plate form being formed at a position protruding from the position of the top plate portion of the hat cross-sectional shape in the first part forming part, and an additional convex shaped form is formed on an ascending slope of a connection portion from the end of the first part forming part to the second part forming part.

[0018] A seventh aspect of the present invention is a T-shaped press-molded part according to the sixth aspect of the present invention, wherein additional convex shapes formed at an ascending slope position of a connection portion from an end portion of the first part forming part to the second part forming part are located on both sides of a top plate of the first part forming part at the position of the connection portion. Effect of the Invention

[0019] According to the above-mentioned means of the present invention, in the first press molding process, the length of the press molding surface of the flat portion of the second part forming portion is increased, thereby making it possible to prevent or suppress the occurrence of wrinkles in the second part forming portion. [Brief description of the drawings]

[0020] [Figure 1] FIG. 2 is a perspective view of the center pillar of the present embodiment as viewed from the outside of the vehicle. [Diagram 2] FIG. 2 is a front view of the center pillar as viewed from the outside of the vehicle. [Diagram 3] FIG. [Figure 4] FIG. 3 is a cross-sectional view showing a schematic cross section taken along line IV-IV in FIGS. 1 and 2. [Diagram 5] 5A to 5C are diagrams sequentially showing forming states in a drawing process of the first press forming step. [Figure 6] 1A to 1C are diagrams sequentially showing the forming state in the pad drawing (grasping and bending) process of the second press forming step. [Figure 7] 10A to 10C are diagrams sequentially showing the formed state in the bending step of the second press-forming step. [Figure 8] FIG. 2 is a plan view (side view of a vehicle) showing a T-shaped press-formed part portion of a center pillar, as viewed from the press-forming direction. [Figure 9] 8. FIG. 8 is a cross-sectional view taken along line VIII-VIII in FIG. [Figure 10] 9 is a cross-sectional view taken along line IX-IX in FIG. 8. [Figure 11] FIG. 1 is a diagram showing a state in which wrinkles occur in a conventional T-shaped press-molded part. [Figure 12] 1A to 1C are diagrams showing a state in which the occurrence of wrinkles is prevented or suppressed in the T-shaped press-molded part of this embodiment. [Figure 13]1 is a plan view (side view of a vehicle) seen from the press molding direction showing a shape in which additional convex portions are formed on both sides of the boundary between a first part forming portion and a second part forming portion in a T-shaped press-molded part of this embodiment. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Hereinafter, an embodiment of the press forming method for a T-shaped press part and a T-shaped press-formed part according to the present invention will be described with reference to the drawings. In the drawings, the arrow FR indicates the vehicle forward direction, the arrow RR indicates the vehicle rearward direction, the arrow UP indicates the vehicle upward direction, and the arrow IN indicates the vehicle width inward direction. Unless otherwise indicated, the directional indications indicate the directions in the drawings themselves.

[0022] [T-shaped pressed parts] First, a T-shaped pressed part to which this embodiment is directed will be described with reference to Figs. 1 to 4, with reference to an upper portion forming member of a center pillar 10 that forms the side framework of an automobile.

[0023] [Center pillar 10] The center pillar 10 is shown in Figs. 1 to 4. Fig. 1 is a perspective view of the center pillar 10 seen from outside the vehicle, Fig. 2 is a front view, and Fig. 3 is a side view. Note that Fig. 1 shows the center pillar 10 installed on the left side of a vehicle such as an automobile in the direction of travel. As explained in the background art section above, the center pillar 10 is disposed as a member that forms the side framework of a vehicle such as an automobile. Note that the center pillar 10 is also known as the B-pillar due to its sequential position in the pillars arranged on the side of the automobile.

[0024] As shown in Fig. 1, the center pillar 10 has an elongated shape extending in the vertical direction of the vehicle. In other words, it is a long-shaped member. And since the center pillar 10 is a structural member that functions as a strength member in the event of a side collision (side impact) of the vehicle, it is formed as a strong structural member. For that reason, high-tensile steel plate is usually used. Also, as shown in Fig. 3, it is formed as a convex curvature shape in the direction in which the side impact load acts, thereby improving its strength.

[0025] The center pillar 10, as viewed from the side of the vehicle, is disposed in an inclined shape with its upper end positioned further rearward than its lower end, as shown in Fig. 2. The center pillar 10 is joined to a roof side rail 18 via a substantially T-shaped mounting portion 16 formed at its upper end. The configuration of the T-shaped mounting portion 16 at the upper end of the center pillar 10 is a T-shaped pressed part that is the subject of this embodiment, which will be described in detail later. The center pillar 10 is joined to a side sill 22 via a substantially T-shaped mounting portion 20 formed at its lower end.

[0026] [Hat-shaped cross-sectional shape] The center pillar 10 is formed with a hat-shaped cross section between the T-shaped mounting portion 16 at the upper end and the T-shaped mounting portion 20 at the lower end. The hat-shaped cross section is shown in FIG. 4. As shown in FIG. 4, the hat-shaped cross section is formed with a top plate portion 24 at the center, flange portions 28 at both end portions, and side plate portions 26 connecting the top plate portion 24 and the flange portions 28. As shown in FIG. 4, the side plate portions 26 are formed to hang down from both end portions of the top plate portion 24, and are composed of a left side plate portion 26L and a right side plate portion 26R. The left and right side plate portions 26L and 26R are formed to expand downward. That is, as shown in FIG. 4, they are formed with a mountain-like inclined shape.

[0027] The flange portion 28 is formed by extending in the left-right direction from the lower end of the side plate portion 26, and is composed of a left flange portion 28L and a right flange portion 28R. The left flange portion 28L is formed and connected to the lower end of the left side plate portion 26L, and the right flange portion 28R is formed and connected to the lower end of the right side plate portion 26R.

[0028] [Press molding process] Next, the press forming process for press forming the center pillar 10 will be described. The press forming process in this embodiment is cold press forming, and is performed in at least two types of press forming processes. In this embodiment, it is performed in a drawing process of the first press forming process 12, and a bending process or pad drawing (holding and bending) process of the second press forming process 14. Fig. 5 shows the drawing process of the first press forming process 12, and Fig. 6 shows the pad drawing (holding and bending) process of the second press forming process 14.

[0029] An intermediate product S2 is formed in a drawing process of a first press molding process 12 shown in Fig. 5, and a final product S3 is formed in a pad drawing (grasping) process of a second press molding process 14 shown in Fig. 6. In both Figs. 5 and 6, for ease of understanding, the press dies used in each press molding process 12, 14 are shown typically, and the upper row shows a state before molding (top dead center), the middle row shows a state during molding, and the lower row shows a state after molding (bottom dead center) in the order of the molding process. In the illustration of the upper row of the pre-molding (top dead center) state, the state in which the upper dies 30, 40 are shown by a two-dot chain line is the top dead center state, and the solid line position state of the upper dies 30, 40 shows the moment when the upper dies 30, 40 descend and contact the molding material S1.

[0030] [First press forming process 12 (drawing process)] First, the drawing process of the first press molding process 12 shown in Fig. 5 will be described. In this embodiment, in the first press molding process 12, press molding is performed to about half of the hat-shaped cross-sectional shape of the center pillar 10. In other words, an intermediate product S2 having a shallow hat-shaped cross-sectional shape is formed. Since the forming in this first press molding process 12 is a drawing process, the present inventors call the forming in the first press molding process 12 "shallow drawing." Note that the forming depth in this first press molding process 12 may be about half of the product shape, or may be drawn to almost the depth of the product shape. The drawing depth differs depending on the shape, such as the depth, of the product.

[0031] As the press mold for the first press forming process 12, a die 32 is disposed as the upper mold 30, and a punch 36 and a blank holder 38 are disposed as the lower mold 34. A flat forming material S1 is disposed between the forming surfaces of the die 32 and punch 36 between the upper mold 30 and the lower mold 34, and the punch 36 and the die 32 move relative to each other (the upper mold 30 moves downward), thereby performing drawing press forming. The drawing process of the first press forming process 12 will be explained step by step below.

[0032] [State before molding in the first press molding process 12] The illustrated state in the upper part of Fig. 5 shows a pre-forming (top dead center) state in the drawing step of the first press forming process 12. In this pre-forming state, a flat forming material S1 is held between the die 32 of the upper mold 30 and the blank holder 38, and is located on the upper surface of the punch 36 of the lower mold 34. In this state, an upward biasing force is applied to the blank holder 38 by a pressure means (not shown), and the forming material S1 is held by the biasing force on the blank holder 38. The pressure means for the blank holder 38 may be a spring means, a rubber, a gas cylinder, a hydraulic cylinder, or the like. For this reason, the blank holder 38 is sometimes called a cushion.

[0033] [Molding process in the first press molding step 12] The illustrated state in the middle of Fig. 5 shows a forming midway state in the drawing step of the first press molding process 12. In this forming midway state, the die 32 of the upper mold 30 moves downward with the forming material S1 held by the blank holder 38. In this state, the forming material S1 comes into contact with the upper surface (forming surface) of the punch 36 of the lower mold 34, and is sequentially pressed by the punch 36. Note that in this state, the lower surface (forming surface) of the die 32 of the upper mold 30 does not come into contact with the forming material S1. Therefore, in this state, intermediate forming of the drawing is performed on the side plate portion 26 of the center pillar 10.

[0034] [State after molding in the first press molding process 12] The illustrated state in the lower part of Fig. 5 shows a post-forming (bottom dead point) state in the drawing step of the first press molding process 12. This post-forming state shows a state in which the above-mentioned mid-forming state has progressed and the die 32 of the upper mold 30 has moved to the bottom dead point in the drawing step of the first press molding process 12. In this state, the mid-forming material S1 shown in the middle part is sandwiched between the die 32 of the upper mold 30 and the punch 36 of the lower mold 34, completing intermediate forming, and forming of the intermediate molded product S2 is completed.

[0035] 5, the linear position indicated by the imaginary line at position 32 of the upper die 30 indicates the position of the molding material S1 in the pre-molding state shown in the upper diagram. Therefore, the illustrated states of the molding material S1 and the intermediate molded product S2 shown in the middle and lower diagrams indicate the change in drawing state from the imaginary line state accompanying the downward movement of the upper die 30 (die 32).

[0036] Therefore, the generation of wrinkles in the press-formed product in the drawing process of the first press-forming step 12, which is a problem of this embodiment, occurs during press forming from the middle to lower stages shown in Fig. 5. The countermeasures of this embodiment for this purpose will be described in detail later.

[0037] [Second press molding process 14 (pad squeezing (grabbing and bending) process)] Next, the pad drawing (grasping and bending) step of the second press molding process 14 shown in Fig. 6 will be described. This pad drawing (grasping and bending) step of the second press molding process 14 is a step for forming the intermediate product S2 formed in the drawing step of the above-mentioned first press molding process 12 into a final product S3 of the center pillar 10. That is, in this pad drawing (grasping and bending) step of the second press molding process 14, the hat depth of the hat-shaped cross-sectional shape of the center pillar 10 is formed to a predetermined depth of the final product shape.

[0038] As for the press die for the pad drawing (grabbing and bending) step of the second press forming process 14, a punch 46 and a blank holder 48 are arranged as a lower die 44, similarly to the drawing step of the first press forming process 12. As for the upper die 40, in the bending step of this second press forming process 14, in addition to the die 42, a pad 49 is also arranged.

[0039] The shape of the molding surface of the press mold in the pad drawing (grasping and bending) process of the second press molding process 14, in particular the shape that forms the hat depth of the hat-shaped cross-sectional shape, is different from the shape of the molding surface of the press mold in the drawing process of the first press molding process 12 that forms the above-mentioned intermediate molded product S2.

[0040] In the pad drawing (grasping and bending) step of the second press molding process 14, the intermediate molded product S2 molded in the drawing step of the first press molding process 12 described above is placed between the molding surfaces of the die 42 and pad 49 of the upper mold 40 and the punch 46 of the lower mold 44, and press molding is performed by relative movement of the upper mold 40 and the lower mold 44 (downward movement of the upper mold 40). The pad drawing (grasping and bending) step of the second press molding process 14 will be explained step by step below.

[0041] [State before molding in the first press molding process 12] The illustrated state in the upper part of Fig. 6 shows a pre-forming (top dead center) state of the pad bending (grasping) step in the second press molding process 14. In this pre-forming state, the die 42 and pad 49 of the upper mold 40 and the punch 36 of the lower mold 44 are spaced apart with a space therebetween. Then, the intermediate molded product S2 molded in the drawing step in the first press molding process 12 is placed between the two 40, 44. In detail, the position of the top plate portion 24 of the intermediate molded product S2 is positioned on the upper surface (molding surface) of the punch 46 and the intermediate molded product S2 is placed.

[0042] In this forming surface (top dead center) state, a biasing force is applied to both the pad 49 of the upper die 40 and the blank holder 48 of the lower die 44 by a pressure applying means (not shown). A downward biasing force is applied to the pad 49, which makes the pad 49 its lowest end position when viewed from the relative positional relationship with the die 42. An upward biasing force is applied to the blank holder 48, which makes its uppermost end position. This uppermost end position is the position of the blank holder 48 when the intermediate formed product S2 is placed on it. As described above, the pressure applying means may be a spring means, rubber, a gas cylinder, a hydraulic cylinder, or the like.

[0043] [Molding process in the second press molding step 14] The illustrated state in the middle of Fig. 6 shows a forming midway state of the pad drawing (grasping and bending) step of the second press forming step 14. In this forming midway state, the die 42 and pad 49 of the upper die 40 move downward, and the pad 49 comes into contact with a position corresponding to the top plate portion 24 of the intermediate formed product S2, and the top plate portion 24 of the intermediate formed product S2 is sandwiched between the die 42 and the punch 46 of the lower die 44. At the same time, the die 42 comes into contact with the position of the flange portion 28 of the intermediate formed product S2, and the flange portion 28 of the intermediate formed product S2 is sandwiched between the die 42 of the upper die 40 and the blank holder 48 of the lower die 44. In other words, the intermediate formed product S2 is in a state of being gripped by the die 42 of the upper die 40 and the blank holder 48 of the lower die 44. In this state, there is still a forming space between the die 42 of the upper die 40 and the punch 46 of the lower die 44.

[0044] In the above state, the positional relationship between the pad 49 of the upper mold 40 and the die 42 is such that the position of the pad 49 in the press operation direction (the vertical direction as viewed in the figure) is slightly retreated from the position of the die 42, as compared to the pre-molding state shown in the upper diagram. In other words, the intermediate molded product S2 has been press-molded by the die 42 to that extent. In detail, the side plate portion 26 has been bent to that extent.

[0045] [State after molding in the second press molding process 14] 6 shows a post-forming (bottom dead point) state of the pad drawing (grasping and bending) step of the second press molding process 14. This post-forming state shows a state in which the above-mentioned intermediate forming state has progressed to the point where the forming space between the die 42 of the upper mold 40 and the punch 46 of the lower mold 44 has disappeared, resulting in the final molded product S3. This completes the press molding of the center pillar 10.

[0046] In the above-mentioned post-forming state, the die 42 of the upper die 40 moves in the press forming direction (downward as viewed in FIG. 6) to the lowest position, the bottom dead center, relative to the punch 46 of the lower die 44. In conjunction with this, the blank holder 48 of the lower die 44 also moves downward relative to the punch 46 against the pressure means, and is positioned so that the flange portion 28 of the final formed product S3 is gripped by the die 42.

[0047] Then, in the state of the above-mentioned bottom dead center position, the forming of the final shape of the side plate portion 26 of the center pillar 10 by the die 42 of the upper mold 40 and the punch 46 of the lower mold 44 is completed.

[0048] Additionally, the pad 49 of the upper die 40 also moves upward relative to the die 42 as the die 42 moves downward. This upward movement continues until there is no more molding space between the die 42 of the upper die 40 and the punch 46 of the lower die 44. This completes the molding of the final shape of the top plate portion 24 of the center pillar 10.

[0049] [Second press forming process 14 (bending process)] Fig. 7 shows an embodiment in which the second press forming process 14 is a bending process. The illustrated states in the upper, middle, and lower parts of Fig. 7 are shown in comparison with the upper, middle, and lower parts of Fig. 6. As can be seen from this illustration, in the bending process, the blank holder 48 in the pad drawing (grasping and bending) process in Fig. 6 is not arranged. The reference numerals given to the bending process in Fig. 7 are shown in comparison with the reference numerals given to the pad drawing (grasping and bending) process in Fig. 6. The forming state is essentially the same, so it will not be described.

[0050] [Description of Features of the Present Embodiment] Next, a press molding method for a T-shaped press part and a T-shaped press-molded part that are characteristic of this embodiment in press molding the above-mentioned center pillar 10 will be described. In the above-mentioned center pillar 10, the part of the T-shaped press-molded part 10 that is the subject of this embodiment is the formation configuration of the part surrounded by a frame S in Figs. 1 and 2. Fig. 8 shows an enlarged view of that part. Note that while Fig. 1 illustrates the center pillar 10 installed on the left side of a vehicle such as an automobile in the traveling direction, Fig. 8 illustrates the center pillar 10 installed on the right side in the traveling direction.

[0051] Therefore, referring to FIG. 8, the T-shaped press-molded part X of this embodiment is composed of a first part forming part A and a second part forming part B. In this embodiment, the first part forming part A refers to a forming part in the center pillar 10 shown in FIGS. 1 to 4, where a hat-shaped cross-sectional shape formed with a top plate part 24, a side plate part 26, and a flange part 28 is arranged in an elongated shape. The second part forming part B is a forming part arranged in a flat shape at an end part of the first part forming part A (the upper end part of the first part forming part A in FIG. 8) in a direction intersecting with the first part forming part A. The second part forming part B is formed integrally and continuously with the first part forming part A, and in the finished product state, the forming position of the flat shape is slightly protruding from the position of the top plate part 24 of the hat-shaped cross-sectional shape in the first part forming part A.

[0052] In the T-shaped press-molded part X shown in Fig. 8 and consisting of the first part forming part A and the second part forming part B of the above-mentioned configuration, the location where wrinkles occur during press molding in the first press molding process 12 is the hatched area in Fig. 8. In this embodiment, this area is referred to as the specific area range Y. The specific area range Y of the second part forming part B is the range of the area obtained by extending the first part forming part A from the end of the first part forming part A in the T-shaped press-molded part X toward the second part forming part B.

[0053] In the press molding of the conventional first press molding process 12, wrinkles W as shown in Fig. 11 were generated in the specific region Y of the second part forming portion B. In order to prevent or suppress the generation of these wrinkles W, the present inventors have created the means described below and taken measures. Note that the wrinkles W generated in the press molding of the first press molding process 12 remain even after the press molding of the second press molding process 14, making it difficult to satisfy the quality requirements of the center pillar 10 as a product.

[0054] 9 and 10 show the configuration of a countermeasure for preventing or suppressing the occurrence of wrinkles W. The countermeasure is to press-form the specific region Y of the second part forming part B described above into a convex shape 50 (a small hill shape) having a height that protrudes above the height position of the top plate part 24 of the first part forming part A in the first press forming process 12.

[0055] The detailed form of the convex shape feature 50 will be described with reference to Figures 9 and 10, where Figure 9 shows a cross section taken along line VIII-VIII in Figure 8, and Figure 10 shows a cross section taken along line IX-IX in Figure 8. In Figures 9 and 10, the shape state indicated by the dashed line P shows a position state in conventional general press molding, and the shape state indicated by the solid line R shows a position state in this embodiment where the convex shape feature 50 (small hill shape) is formed and press molded. Note that the height position K of the second part forming portion B in Figure 9 shows the height of the center pillar 10 as a finished product after the second press molding process 14 is completed.

[0056] The height h of the convex shape feature 50 shown in Fig. 10 is 8 mm in this embodiment. As can be seen from the illustrated state in Fig. 9, this height h is set to be lower than the formed height K of the flat shape feature of the second part forming portion B press-formed in the second press-forming process 14. In other words, the height of the convex shape feature 50 (hill shape) is set to be equal to or lower than the height to be bent up in the second press-forming process 14.

[0057] [Functions and effects of the first press molding step in the above-described embodiment] According to the above-described embodiment, in the first press molding process 12, a convex shape 50 (small hill shape) is formed by press molding in the specific region Y of the T-shaped press-molded part X. This allows the line length of the press-molded surface in the specific region Y of the second part forming part B to be longer than in the past, making it possible to prevent or suppress the occurrence of wrinkles in the second part forming part B. Fig. 12 shows the state of the second part forming part B after molding in the first press molding process 12. It can be seen from Fig. 12 that the occurrence of wrinkles W is almost completely prevented or suppressed.

[0058] [Additional embodiment added to the above embodiment] Next, an additional embodiment added to the basic embodiment described above will be described. In this additional embodiment, in the press molding of the second press molding process 14, an additional convex shape form 52 is set at an ascending slope position 54 of the connecting portion from the end of the first part forming portion A to the second part forming portion B, and press molding is performed. Fig. 13 shows the position where the additional convex shape form 52 is set. Note that the additional convex shape form 52 may be a concave shape form. Even if it is a concave shape form, the same action and effect as in the case of the additional convex shape form 52 described later can be obtained.

[0059] The positions at which the additional convex shape features 52 shown in Fig. 13 are formed are on both sides of the top plate portion 24 at the ascending inclined surface position 54 of the connecting portion. The inclined surface position 54 at which the additional convex shape features 52 are formed is explained with reference to Fig. 9, and is a position leading to position K shown as the finished product height in the second part forming portion B. In Fig. 9, this position is indicated by reference numeral 54, and the position at which the additional convex shape features are formed is indicated by reference numeral 52.

[0060] In FIG. 13, the additional convex shape 52 is formed in two places on both sides of the top plate portion 24, but the additional convex shape 52 may be formed continuously by connecting these two places.

[0061] [Effects of the Additional Embodiment] According to the additional embodiment described above, in the press molding of the second press molding process 14, the additional convex shape form 52 is set at an ascending inclined surface position 54 of the connecting portion from the end portion of the first part forming portion A to the second part forming portion B. This makes it possible to increase the line length of the press molding surface at the inclined surface position 54, and thus makes it possible to reliably prevent or suppress the occurrence of wrinkles W at the inclined surface position 54.

[0062] The additional convex shape form 52 is formed as press molding in the second press molding process 14, and also becomes the product shape after molding in the second press molding process 14. The additional convex shape form 52 as the product shape also has the effect of improving the strength of the formation position, that is, the ascending slope position 54 of the connection portion from the end of the first part forming portion A to the second part forming portion B.

[0063] Other embodiments Although specific embodiments of the present invention have been described above, the present invention can be embodied in a variety of other forms.

[0064] For example, in the above embodiment, a T-shaped press part formed on the center pillar 10 of an automobile has been described. The present invention can also be applied to T-shaped press parts formed on other parts forming the frame of an automobile.

[0065] In the above embodiment, the press forming process is described as being the drawing process of the first press forming process 12, and the pad drawing (grasping and bending) process and bending process of the second press forming process 14, but other press forming processes may be included. For example, a trimming process may be included.

[0066] [Effects of each invention described in "Means for solving the problems"] Finally, the effects of each invention in the above-mentioned "Means for Solving the Problems" are listed below.

[0067] First, according to the first invention, in the first press molding process, the specific region of the second part forming part is press molded into a convex shape. As a result, in the first press molding process, the line length of the press molded surface of the specific region of the second part forming part becomes longer than in the conventional method. Therefore, it is possible to prevent or suppress the occurrence of wrinkles in the second part forming part.

[0068] Next, according to the second invention, the forming height of the convex shape set in the specific region of the second component forming portion in the above-mentioned first invention is set to be lower than the forming height of the flat shape of the second component forming portion press-formed in the second press-forming step. This allows press-forming to be performed with high precision without affecting the second press-forming step of the second component forming portion.

[0069] Next, according to the third invention, in the press molding of the second press molding step, an additional convex shape is set at the ascending slope position of the connecting portion from the end of the first part forming part to the second part forming part, and press molding is performed. This makes it possible to increase the line length of the press molding surface at the slope position, and reliably prevent or suppress the occurrence of wrinkles at the slope position.

[0070] According to the fourth aspect of the present invention, the positions of the convex shapes set at the ascending slope positions of the connection portion from the end of the first component forming portion to the second component forming portion are set at both sides of the top plate of the first component forming portion at the connection portion position, whereby, because the positions are locations where wrinkles are likely to occur, it is possible to more efficiently prevent or suppress the occurrence of wrinkles.

[0071] According to a fifth aspect of the present invention, the T-shaped press part is a component for forming an upper portion of a center pillar that forms the side framework of an automobile, thereby making it possible to prevent or suppress the occurrence of wrinkles during press forming of the center pillar.

[0072] Next, according to the T-shaped press-molded part of the sixth aspect of the invention, it is possible to obtain the same effects as those obtained by the press-molding method for the T-shaped press-molded part of the third aspect of the invention described above.

[0073] Next, according to the T-shaped press-molded part of the seventh aspect of the invention, it is possible to obtain the same effects as those obtained by the press-molding method for the T-shaped press-molded part of the fourth aspect of the invention described above. [Explanation of symbols]

[0074] 10 Center pillar 12 First press forming process 14 Second press forming process 16 Mounting part 18 Roof side rail 20 Mounting part 22 Side sill 24 Top plate 26 Side plate part 26L Left side panel 26R Right side panel 28 Flange 28L Left flange 28R Right flange 30 Upper die (for the first press molding process) 32 Die (for the first press molding process) 34 Lower die (for the first press forming process) 36 Punch (for the first press forming process) 38 Blank holder (for the first press forming process) 40 Upper die (for the second press molding process) 42 Die (for the second press molding process) 44 Lower die (for the second press forming process) 46 Punch (for the second press forming process) 49 Pad 48 Blank holder (for the second press forming process) 50 Convex form 52 Additional convex form 54 Uphill slope position A 1st part forming section B 2nd part forming section XT-shaped press-molded parts Y Specific area range R Height position of convex shape K Forming height of the second part forming part of the finished product h Height of the convex shape W wrinkles

Claims

1. the T-shaped press part is formed with a first part forming part formed by arranging a hat-shaped cross-sectional shape having a top plate portion, a side plate portion, and a flange portion in a long shape, and a second part forming part disposed in a flat plate form at an end of the first part forming part in a direction intersecting the first part forming part, formed integrally and continuously with the first part forming part, the flat plate form being formed at a position protruding from the position of the top plate portion of the hat cross-sectional shape in the first part forming part, The T-shaped press part is formed by a press molding method having at least a first press molding step and a second press molding step, a press molding method for a T-shaped press part, in which in the first press molding step, a specific region of the second part forming part in a region obtained by extending the first part forming part from an end of the first part forming part in the T-shaped press part toward the second part forming part is press-molded into a convex shape having a height protruding above a height position of a top plate portion of the first part forming part.

2. A press molding method for the T-shaped press part according to claim 1, a forming height of a convex shape formed in a specific region of the second part forming part in the first press molding process is set to be lower than a forming height of a flat shape of the second part forming part which is press molded in the second press molding process.

3. A press molding method for producing a T-shaped press part according to claim 2, a press molding method for a T-shaped press part, in which, in the press molding of the second press molding step, an additional convex shape is set at an ascending slope position of a connection portion from an end portion of the first part forming part to the second part forming part, and press molding is performed.

4. A press molding method for producing a T-shaped press part according to claim 3, a press molding method for a T-shaped press part, wherein an additional convex shape is set at an ascending slope position of a connection portion from an end portion of the first part forming part to a second part forming part, the additional convex shape being set at both sides of a top plate of the first part forming part at the connection portion position.

5. A press molding method for a T-shaped press part according to any one of claims 1 to 4, The press molding method for a T-shaped press part, wherein the T-shaped press part is a member forming an upper portion of a center pillar that forms the side framework of an automobile.

6. a first part forming part formed by arranging a hat-shaped cross-sectional shape having a top plate portion, a side plate portion, and a flange portion in an elongated shape; and a second part forming part disposed in a flat plate shape at an end of the first part forming part in a direction intersecting the first part forming part and formed integrally and continuously with the first part forming part, the flat plate shape being formed at a position protruding from the position of the top plate portion of the hat-shaped cross-sectional shape in the first part forming part, A T-shaped press-molded part, wherein an additional convex shape is formed at an upwardly inclined surface position of a connection portion from an end portion of the first part forming part to a second part forming part.

7. 7. The T-shaped press-formed part according to claim 6, a top plate of the first part forming part at a position of the connecting portion, the top plate being formed on one side of the first part forming part;

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