阅读说明：本技术 用于车辆用构造部件的加强部件及其制造方法 (Reinforcing member for vehicle structural member and method for manufacturing same ) 是由 小坂洋康 于 2019-06-28 设计创作，主要内容包括：本发明涉及一种用于车辆用构造部件的加强部件,其具备：顶板部、和从该顶板部的两端延伸的一对纵壁部,在上述一对纵壁部中的至少一个纵壁部形成有用于安装其他的车辆构成部件的平面部,上述平面部的在对上述加强部件冲压成型时的冲压方向前方侧的端缘形成为向冲压方向呈凸状的曲线形状。(The present invention relates to a reinforcing member for a structural member for a vehicle, including: the vehicle component mounting structure includes a top plate portion and a pair of longitudinal wall portions extending from both ends of the top plate portion, wherein a flat surface portion for mounting another vehicle component is formed in at least one of the pair of longitudinal wall portions, and an end edge of the flat surface portion on a front side in a pressing direction in press forming the reinforcement member is formed in a curved shape protruding in the pressing direction.)

1. A reinforcing member for a structural member for a vehicle, characterized in that,

the disclosed device is provided with: a top plate part and a pair of vertical wall parts extending from two ends of the top plate part,

a planar portion for mounting another vehicle component is formed on at least one of the pair of vertical wall portions,

the edge of the planar portion on the front side in the pressing direction when the reinforcing member is press-formed is formed in a curved shape protruding in the pressing direction.

2. The reinforcing component of claim 1,

the structural member for a vehicle is a pillar provided at a side portion of the vehicle, and the reinforcing member is a hinge reinforcement that reinforces the pillar.

3. The reinforcing component of claim 1 or 2,

the other vehicle component is a striker for locking a door of the vehicle, and the striker is attached to the flat surface portion.

4. A method of manufacturing the reinforcing member for a structural member for a vehicle according to any one of claims 1 to 3,

comprises a step of press-molding the reinforcing member with a press mold,

the press forming die comprises: the press forming apparatus includes a first die surface corresponding to the planar portion of the longitudinal wall portion, and a second die surface corresponding to a portion of the longitudinal wall portion adjacent to the planar portion, the first die surface having a curved shape that is convex in a press direction compared to the second die surface.

5. The method of claim 4,

the press forming step includes a step of drawing the reinforcing member by a drawing die and a step of bending the drawn reinforcing member by a bending die,

the drawing die and the bending die each have a first die surface having the convex curved shape.

Technical Field

The present invention relates to a reinforcing member for a structural member for a vehicle and a manufacturing method thereof.

Background

Generally, a pillar is provided as a vehicle structural member in a side portion of a vehicle such as an automobile. As for the pillars, there are a front pillar commonly called an a pillar, a center pillar commonly called a B pillar, and a rear pillar commonly called a C pillar from the front of the automobile. In order to cope with a side collision (side collision) of an automobile, the pillar is required to have structural strength. Therefore, a reinforcing member called a hinge reinforcement is provided in the center pillar to reinforce the strength thereof.

A mounting portion for mounting other vehicle components around the pillar may be provided. Accordingly, corresponding strength is also required for the columns. For example, a striker that locks a door (door) provided on a side portion of a vehicle in a closed state is disposed in a center pillar. A flat surface portion for mounting the striker is formed in the hinge reinforcement serving as a reinforcing member of the center pillar.

The center pillar is elongated and is formed in a closed cross section by an outer panel having a hat-shaped cross section and a flat inner panel. A hinge reinforcement is disposed in the closed cross section and is joined to the outer panel by welding or the like to reinforce the center pillar.

The hinge reinforcement is disposed in the closed cross section of the center pillar, and is formed in an elongated shape having a cross section corresponding to the shape of the inner surface of the outer panel having a hat-shaped cross section, in the shape of an コ letter. The コ -shaped cross section is formed by a top plate portion at the center in the width direction (vehicle front-rear direction), and a pair of vertical wall portions that are formed by bending from ridge lines at both ends in the width direction of the top plate portion and are arranged to extend. In addition, a planar portion for attaching the striker, which is the other component, is formed in the hinge reinforcement and the vertical wall portion.

Further, the molding of the hinge reinforcement is performed by punching. 1-piece steel sheet is bent by press forming to form an コ -shaped cross section (see japanese patent application laid-open No. 2013-220807). In general, a press-forming die for drawing and a press-forming die for bending are used for press-forming.

In addition, techniques belonging to the art are described in Japanese patent laid-open Nos. 2002-254114 and 2015-66584.

However, the material of the hinge reinforcement tends to have higher material strength due to the recent demand for improved side collision performance. In the case of using a high-strength material in press molding, it is difficult for wrinkles (creases) on a forming body once generated in the press molding process to collapse and achieve planarization in the forming process thereof. That is, even if wrinkles occur during the molding process when the material strength is not high, the wrinkles can be crushed and flattened during the final press molding of the molding. However, in the case of a high-strength material, once wrinkles occur, the wrinkles are difficult to crush in a subsequent press molding process due to the high strength. Furthermore, it is difficult to remove the wrinkles by other means after the press forming. Here, the wrinkles as a problem mean undulations generated in press forming.

Therefore, in the case where a high-precision planar shape without wavy wrinkles is required after press forming, such as the planar portion for mounting the striker formed on the vertical wall portion of the hinge reinforcement, it is necessary to perform press forming so as not to generate wrinkles during press forming.

In this way, when a reinforcing member having a flat portion for attaching another component is press-formed, it is desired to prevent or suppress the occurrence of undulation or wrinkles in the flat portion even with a high-strength material.

Disclosure of Invention

One aspect of the present invention is a reinforcing member for a structural member for a vehicle, including: the vehicle component mounting structure includes a top plate portion and a pair of longitudinal wall portions extending from both ends of the top plate portion, wherein a flat surface portion for mounting another vehicle component is formed in at least one of the pair of longitudinal wall portions, and an end edge of the flat surface portion on a front side in a pressing direction in press forming the reinforcement member is formed in a curved shape protruding in the pressing direction.

According to an embodiment, the structural member for a vehicle is a pillar provided at a side portion of the vehicle, and the reinforcing member is a hinge reinforcement for reinforcing the pillar.

According to an embodiment, the other vehicle component is a striker for locking a door of the vehicle, and the striker is attached to the flat surface portion.

Another aspect of the present invention is a method for manufacturing a reinforcing member for a structural member for a vehicle, including a step of press-forming the reinforcing member by a press-forming die having: the press machine includes a first die surface corresponding to the flat surface portion of the vertical wall portion, and a second die surface corresponding to a portion of the vertical wall portion adjacent to the flat surface portion, wherein the first die surface has a curved shape that is convex in a press direction with respect to the second die surface.

According to an embodiment, the press forming step includes a step of drawing the reinforcing member by a drawing die and a step of bending the drawn reinforcing member by a bending die, and the drawing die and the bending die each have the first die surface having the convex curved shape.

According to the embodiment, even when a vehicle reinforcing member having a flat mounting surface portion for mounting another component is press-formed using a high-strength material, it is possible to prevent or suppress occurrence of wrinkles, which undulate in the flat mounting surface portion, during the press-forming.

Drawings

Fig. 1 is an overall view showing an example of a center pillar disposed at a side portion of a vehicle such as an automobile.

Fig. 2 is a sectional view taken along line II-II of the center pillar of fig. 1.

Fig. 3 is a front view of the top plate portion of the hinge reinforcement after the second step (final form) as viewed from the vehicle outside.

Fig. 4 is a side view showing a longitudinal wall portion on the vehicle rear side seen from the hinge reinforcement shown in fig. 3 as viewed from the direction of arrow IV.

Fig. 5 is a side view showing a longitudinal wall portion on the vehicle front side as seen from the hinge reinforcement shown in fig. 3 viewed in the direction of arrow V.

Fig. 6 is an enlarged view showing a plane portion for mounting the striker on the hinge reinforcement shown by a circle VI in fig. 5 in an enlarged manner.

Fig. 7 is an enlarged perspective view of a welding projection formed on a vertical wall portion of the hinge reinforcement.

Fig. 8 is a conceptual diagram showing a schematic configuration of a drawing step of the hinge reinforcement.

Fig. 9 is a conceptual diagram showing a schematic configuration of a bending step of the hinge reinforcement.

Fig. 10 is a sectional view showing a state in which the striker is attached to the center pillar.

Fig. 11 is a front view of the top plate portion of the hinge reinforcement after the first step (after the drawing step) as viewed from the vehicle outside.

Fig. 12 is a side view showing a vertical wall portion on the vehicle rear side as seen from the hinge reinforcement shown in fig. 11 as viewed in the direction of arrow XII.

Fig. 13 is a side view of the vertical wall portion on the vehicle front side as viewed from the direction of arrow XIII of the hinge reinforcement shown in fig. 11.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In one embodiment, the structural member for a vehicle is a center pillar that is one of pillars provided at a side portion of a vehicle such as an automobile, and the reinforcing member is a hinge reinforcement that reinforces the center pillar. In addition, the term "direction" used in the following description basically refers to a direction with reference to a vehicle in a normal posture. IN each figure, the vehicle forward direction is indicated by an arrow FR, the vehicle upward direction is indicated by an arrow UP, and the vehicle inward direction is indicated by an arrow IN.

Fig. 1 shows an external appearance of a center pillar 10 for a vehicle such as an automobile, and fig. 2 shows a cross section of the center pillar 10 shown in fig. 1 cut at a line II-II. The center pillar 10 in fig. 1 is a left pillar of the vehicle. In addition to the center pillar 10, a front pillar (not shown) and a rear pillar (not shown) are disposed as vehicle structural members on the side portion of the vehicle. Among these pillars, the strength of the center pillar 10 is particularly important in response to the demand for a side collision (side collision) of the automobile. Therefore, as shown in fig. 2, a hinge reinforcement 20 is disposed as a reinforcing member in the center pillar 10 to reinforce the strength thereof. As one embodiment, a high-tensile steel sheet is used as described below in response to the recent demand for higher strength.

As shown in fig. 1 and 2, the center pillar 10 includes: an elongated outer panel 12 constituting the vehicle outer side, and an elongated inner panel 14 constituting the vehicle inner side. The center pillar 10 further includes a hinge reinforcement 20 disposed inside the outer panel 12.

The outer panel 12 has a hat-shaped cross section that opens toward the vehicle interior, and is composed of a top plate portion 12A, a vertical wall portion 12B, and a flange portion 12C. The roof portion 12A is disposed on the vehicle outer side (lower side as viewed in fig. 2), and the pair of left and right vertical wall portions 12B extend inward (upper side as viewed in fig. 2) from both ends thereof. The pair of left and right vertical wall portions 12B are inclined inward (upward as viewed in fig. 2) in such a direction that the interval therebetween increases. The flange portions 12C project in opposite directions from the inner (upper side as viewed in fig. 2) ends of the pair of vertical wall portions 12B. Further, the flange portion 12C extends in the same direction as the top plate portion 12A.

In the following description, when it is necessary to describe the first vertical wall portion 12B and the first flange portion 12C which are arranged in bilateral symmetry, the member arranged on the vehicle rear side (right side) as viewed in fig. 2 is denoted by r after the reference numeral of the member, and the member arranged on the vehicle front side (left side) is denoted by f.

As shown in fig. 2, the inner panel 14 is formed in a substantially flat plate shape, and flange portions 14C extend and protrude outward from both side edge portions (both right and left end portions as viewed in fig. 2) on the vehicle front side and the vehicle rear side. The flange portions 14C of the inner panel 14 and the flange portions 12C of the outer panel 12 are overlapped in the vehicle width direction and joined by spot welding to form a closed cross section. Note that the welding portion is indicated by a black circle in fig. 1 and by an x mark in fig. 2. The welding is not limited to spot welding, and may be performed by other methods such as laser welding.

As shown in fig. 1, the center pillar 10 is arranged in the vehicle to extend in the up-down direction. The center portion of the center pillar 10 in the longitudinal direction is formed in a gently curved shape protruding outward in a convex manner. The center pillar 10 is inclined in a direction toward the rear of the vehicle from the upper end to the lower end.

As shown in fig. 1 and 2, the elongated center pillar 10 is formed in a closed cross-sectional configuration, and forms an inner space inside. The center pillar 10 is joined to a roof side rail 18 via a substantially T-shaped mounting portion 16 formed at an upper end of the outer panel 12. The center pillar 10 is joined to a side sill 19 via a substantially T-shaped attachment portion 17 formed at the lower end of the outer panel 12.

The outer panel 12 is a steel plate member having a tensile strength of 1180MPa or more. As an embodiment, a high tensile steel plate of 1470MPa is used. The outer panel 12 is formed by normal temperature stamping, cold stamping, or hot stamping. The inner panel 14 is made of a steel plate member having the same tensile strength as the outer panel 12 or a lower tensile strength than the outer panel 12. As an embodiment, a 590MPa steel plate member is used. The inner panel 14 is formed by normal temperature pressing.

Next, the hinge reinforcement 20 disposed in the inner space of the center pillar 10 will be described. As clearly shown in fig. 2, the hinge reinforcement 20 is disposed along the inner surface of the outer panel 12 of the center pillar 10. The hinge reinforcement member 20 is composed of a top plate 20A and a vertical wall 20B.

The hinge reinforcement 20 is disposed along the inner surface of the outer panel 12 of the center pillar 10 as described above, and thus has a cross section substantially shaped like コ. The top plate 20A is disposed inside the top plate 12A of the outer panel 12. The left and right vertical wall portions 20B are disposed inside the vertical wall portion 12B of the outer panel 12 as viewed in fig. 2, and are integrally connected inward (upward as viewed in fig. 2) from a ridge line L1 at both ends of the top panel portion 20A. The left and right vertical wall portions 20B are inclined inward (upward as viewed in fig. 2) in such a direction that the interval therebetween increases, similarly to the vertical wall portion 12B.

In addition, when it is necessary to show the vertical wall portion 20B of the hinge reinforcement 20 arranged in bilateral symmetry in a left-right manner as in the case of the outer panel 12, a member arranged on the vehicle rear side (right side as viewed in fig. 2) is denoted by r after the reference numeral of the member, and a member arranged on the vehicle front side (left side as viewed in fig. 2) is denoted by f.

However, an open/close door (not shown) of the vehicle is disposed in front and rear (left and right positions as viewed in fig. 1) of the center pillar 10 shown in fig. 1. A front door (front door) is disposed at the front portion of the center pillar 10, and a rear door (rear door) is disposed at the rear portion. The front door is opened and closed by a door hinge provided at the front pillar, and the front door is locked to the center pillar 10 by a striker 30 attached to the center pillar 10. The striker 30 is disposed below the front side of the center pillar 10 as shown in fig. 1. The cross-sectional position of the center pillar in fig. 2 is different from the position where the striker 30 is provided, but the striker 30 is shown by a two-dot chain line in fig. 2 because the position of the striker 30 in the front-side vertical wall portions 12Bf, 20Bf is shown as an image.

Fig. 10 shows a specific structure in which the striker 30 is disposed in the center pillar 10. Note that the outer panel 12, the inner panel 14, and the hinge reinforcement 20 are drawn without thickness in this figure. As can be seen from fig. 10, the striker 30 is disposed on the front side vertical wall portions 12Bf and 20Bf of the outer panel 12 and the hinge reinforcement 20. The striker mounting seat 31 is fixed and attached to the vertical wall portions 12Bf and 20Bf by a fastening device 36 such as a bolt and a nut. Further, disposed on the outer side of the outer panel 12 is a decorative panel 38.

Fig. 3 to 5 show the entire structure of the hinge reinforcement member 20. The hinge reinforcement member 20 shown in fig. 3 to 5 is a product after press forming, which will be described later. Fig. 3 is a view of the top plate portion 20A of the hinge reinforcement member 20 as viewed from the outside. Fig. 4 shows a vertical wall portion 20Br on the vehicle rear side as seen from the hinge reinforcement 20 of fig. 3 viewed in the direction of arrow IV. Fig. 5 shows a vertical wall portion 20Bf on the vehicle front side as seen from the hinge reinforcement 20 shown in fig. 3 when viewed in the direction of arrow V. As clearly shown in these figures, the hinge reinforcement 20 is formed in a long shape, and is formed in a shape gently curved in a convex shape toward the outside as shown in fig. 4 and 5.

The hinge reinforcement 20 is formed by punching. In addition, in order to improve the side collision performance, a high tensile steel plate is used as a material for press forming. The tensile strength is 980MPa or more. As one embodiment, 1180MPa high tensile steel plate is used. The thickness of the steel sheet is, for example, about 1mm to 2mm, and 1 high-tension steel sheet is press-formed by normal temperature punching, cold punching, or hot punching.

Although not shown in fig. 3 to 5, the top plate portion 20A of the hinge reinforcement 20 is welded to the inner surface of the top plate portion 12A of the outer panel 12 of the center pillar 10 by spot welding, as shown in fig. 2. Therefore, the welding protrusion 22 for forming the welding seat surface 23 in the top plate portion 20A protrudes outward of the vehicle by a predetermined height. The welding protrusions 22 are discontinuously arranged along the vehicle vertical direction.

The outer surface of the welding projection 22, i.e., the welding seat surface 23, is formed in a flat shape as shown in fig. 2 in order to ensure the bonding strength with the top plate portion 12A of the outer panel 12 by spot welding. The shape of each welding protrusion 22 may be formed in a semicircular shape or a circular shape as one embodiment, but may be formed in various shapes such as a rectangular shape, a triangular shape, an elliptical shape, and a hexagonal shape as other embodiments.

The center pillar 10 and the hinge reinforcement 20 are welded between the vertical wall portion 12B of the outer panel 12 and the vertical wall portion 20B of the hinge reinforcement 20 at a position indicated by a symbol x in fig. 2. Therefore, the welding protrusions 25 for forming the welding seat surfaces 26 are provided on the pair of vertical wall portions 20Br and 20Bf of the hinge reinforcement 20 shown in fig. 4 and 5. However, the welding protrusion 25 is omitted from the pair of vertical wall portions 20Br and 20Bf shown in fig. 4 and 5. The welding protrusions 25 are formed to protrude toward the pair of vertical wall portions 12B of the outer panel 12, and are discontinuously arranged in the vehicle vertical direction. The inner surface of the vertical wall portion 12B is joined to the welding seat surface 26 of the surface of the welding protrusion 25 by spot welding.

Fig. 7 schematically shows the welding projection 25 formed on the vertical wall portion 20B of the hinge reinforcement 20. Each of the welding protrusions 25 protrudes from the vertical wall portion 20B to the outside of the hinge reinforcement 20 by a predetermined height T1. As shown in fig. 2 and 7, each welding protrusion 25 protrudes outward of the hinge reinforcement 20 over the entire width from each ridge line L1 formed between the pair of vertical wall portions 20B and the top plate portion 20A to the end edge of the vertical wall portion 20B on the vehicle interior side. The width W1 of each welding projection 25 at the edge on the ridge line L1 side is narrower than the width W2 at the edge on the vehicle interior side, and is formed in a laterally inverted trapezoidal shape as viewed from the front. Further, the end portion of each welding projection 25 on the side of the ridge line L1 is ground obliquely toward the ridge line L1.

The outer surface of each welding projection 25, that is, the welding seat surface 26 is formed in a flat shape as shown in fig. 2 and 7 in order to ensure the bonding strength with each vertical wall portion 12B of the outer panel 12 by spot welding. Therefore, each welding seat face 26 is formed in a flat shape extending from the end edge 27 on the side of each ridge line L1 to the end edge on the vehicle interior side of the vertical wall portion 20B, and the length of the end edge 27 on the side of the ridge line L1 is narrower than the length of the end edge 28 on the vehicle interior side, and is formed in a laterally inverted trapezoidal shape as viewed from the front.

A planar portion 32 for attaching a striker 30 for locking the front door in a closed position is formed in a lower partial range of the vertical wall portion 20Bf on the vehicle front side of the hinge reinforcement 20 shown in fig. 5. The hatched portion in fig. 5 is a flat surface portion 32 for mounting the striker. This part is shown enlarged in fig. 6. In fig. 6, the position where the striker 30 is arranged is shown by a two-dot chain line. The striker 30 is attached to the outer panel 12 and the vertical wall portion 12B and the vertical wall portion 20B of the hinge reinforcement 20 via a striker attachment seat 31 having a flat plate shape to which the striker 30 is fixed. Therefore, the planar portion 32 for mounting the striker is required to have a planar shape without undulation or wrinkles.

The flat surface portion 32 shown in fig. 6 is formed by press forming into a convex shape in which an end edge 32A on the vehicle interior side bulges toward the vehicle interior side (downward as viewed in fig. 6). The convex shape is, for example, a smooth and gentle curved shape. The flat surface portion 32 is formed by press-molding the hinge reinforcement member 20.

Next, a method of manufacturing the hinge reinforcement member 20 by press molding will be described with reference to fig. 8 and 9. In this method, drawing is performed as a first step, and bending is performed as a second step. Fig. 8 shows the arrangement of the dies in the drawing step, and fig. 9 shows the arrangement of the dies in the bending step. These drawings are for explaining the press forming of the flat surface portion 32 in the cross section taken along line VII-VII in fig. 5. In fig. 4 and 5, the punching direction on the hinge reinforcement member 20 is shown by a hollow arrow P.

Fig. 8 shows a drawing step in the first step. The drawing mold includes a fixed-side lower mold 40, a movable-side upper mold 42, and cushion molds 44 disposed on both sides of the lower mold 40. The upper die 42 integrally includes a portion 42A formed by drawing the front vertical wall 20Bf and a portion 42B formed by drawing the rear vertical wall 20 Br. The buffer die 44 follows the operation of the drawing upper die 42.

Next, the die surface shape of the portion 42A of the upper die 42 where the vertical wall portion 20Bf of the hinge reinforcement 20 is molded will be described. As shown by a solid line as D1 in fig. 5 and 6, the die surface forms a portion of the striker mounting flat surface portion 32 into a convex shape corresponding to the end edge 32A of the flat surface portion 32 on the press direction front side. That is, the vertical wall portion 20Bf is formed in a smoothly and gently curved shape bulging toward the front side in the press direction with respect to the die surface for forming the portion adjacent to the flat portion 32. The die surface shape of the flat surface portion 32 which is not formed into a normal convex shape is shown by a broken line D1 a. The usual die face position is also shown in dashed lines in fig. 8. The die surface having a convex shape means that the drawing depth at the position of the flat surface portion 32 is deeper than the periphery.

Fig. 9 shows a bending step in the second step. The bending mold includes a fixed-side lower mold 50, a movable-side upper mold 52, and a pad 54 for pressing a press-molded product. The upper die 52A of the upper die 52 that bends the vertical wall portion 20Bf is independent of the upper die 52B that bends the vertical wall portion 20 Br. The spacer 54 fixes the work (workpiece) obtained by drawing in the first step to the lower die 50, and performs bending while pressing the workpiece with the spacer 54.

As described above, the punch surface shape of the upper die 52A for bending the vertical wall portion 20Bf is formed in the same shape as the punch surface shape of the portion 42A of the upper die 42 for forming the vertical wall portion 20Bf in the drawing. That is, the die surface of the upper die 52A is formed into a shape indicated by a solid line D2 in fig. 5 and 6. In the bending in the second step, the die surface of the upper die 52A for molding the striker-mounting flat surface portion 32 is a convex shape corresponding to the end edge 32A of the flat surface portion 32 on the press-direction front side. That is, the vertical wall portion 20Bf is formed in a smoothly and gently curved shape bulging toward the front side in the press direction with respect to the die surface forming the portion adjacent to the flat portion 32. Note that, as in the case of the drawing in the first step, a normal die surface position is shown by a broken line D2 a.

As described above, the hinge reinforcement member 20 is press-formed by the drawing step in the first step and the bending step in the second step. Fig. 11 to 13 show the state of the hinge reinforcement member 20 during the molding after the drawing step in the first step. The final form of the hinge reinforcement member 20 after the bending step in the second step is the form shown in fig. 3 to 5 described above. Fig. 11, which shows a state during molding, is a view of the top plate portion 20A of the hinge reinforcement 20 as viewed from the outside of the vehicle. Fig. 12 shows a vertical wall portion 20Br on the vehicle rear side as seen from the hinge reinforcement 20 of fig. 11 viewed in the direction of arrow XII. Fig. 13 shows a vertical wall portion 20Bf on the vehicle front side as seen from the hinge reinforcement 20 shown in fig. 11 as viewed in the direction of arrow XIII. Also, the punching direction is shown by the hollow arrow P in these figures. The press-molding of the hinge reinforcement member 20 is performed by pressing in the direction of the arrow P. Note that, the welding protrusions 22 and 25 in fig. 11 to 13 are not shown in the same manner as in fig. 3 to 5.

In fig. 9 showing the bending in the second step, the two-dot chain line shows the cross-sectional shape of the vertical wall portion 20B of the hinge reinforcement 20 (fig. 11 to 13) after the drawing in the first step shown in fig. 8. From this shape, as shown by an arrow in fig. 9, the upper die 52 for bending is pressed into a solid line shape.

In the press molding, the planar portion 32 for mounting the striker formed in the vertical wall portion 20Bf on the vehicle front side is press molded. In the press forming of the flat portion 32, the die surface shape of the end edge on the front side in the press direction of the upper dies 42A and 52A formed in the flat portion 32 is convex in the press direction in the drawing step in the first step and the bending step in the second step. In the press forming in the two steps, the end edge on the front side in the press direction is formed by pressing from the center of the convex shape to both sides, and the excess thickness during the press forming is not accumulated in the flat surface portion 32 and is transferred to and removed from both sides. As a result, surface undulations are not generated in the flat surface forming portion in the press forming of the flat surface portion 32. That is, the generation of wrinkles due to surface undulations is prevented and suppressed.

When high tensile steel is used as a material for press forming, if wrinkles such as surface undulations are generated in the flat surface forming portion during press forming, it is difficult to crush the wrinkles and achieve a planar shape. Since the die surface for forming the striker mounting flat surface portion 32 is formed in a convex shape from the drawing step in the first step as described above, the occurrence of wrinkles is prevented and suppressed even during the press forming. This enables the flat surface portion 32 to be formed into a highly accurate flat surface. As a result, the striker 30 can be reliably attached to the flat surface portion 32 with high accuracy.

In the present embodiment, the press forming is performed by two steps of drawing and bending. Therefore, the trajectory of the impact line is formed by the drawing on the work (workpiece) formed by the drawing step. The impact line does not disappear by subsequent bending, but does not affect the flatness.

In the above embodiment, the structural member for a vehicle is a center pillar and the reinforcing member is a hinge reinforcement for the center pillar, but as another embodiment, another pillar and a reinforcing member for the pillar may be used. Further, a structural member for a vehicle other than the pillar and a structural member for a vehicle used for the same may be used.

The other component of the vertical wall portion of the hinge reinforcement attached to the reinforcing member is a striker for locking the vehicle door, but may be a component other than the striker as another embodiment.

Further, the other constituent members are disposed on the vertical wall portion on one side of the hinge reinforcement, but may be disposed on the vertical wall portions on both sides as another embodiment.

The hinge reinforcement is press-formed by two steps of drawing and bending, but may be formed by one step or three or more steps as another embodiment.

In the embodiment described above, the vertical wall portion of the reinforcement member is formed with the flat surface portion for attaching another vehicle component, and the end edge of the flat surface portion on the front side in the pressing direction when the reinforcement member is press-formed is formed in a curved shape convex in the pressing direction. Therefore, when the flat surface portion is press-formed, the end edges in the forming direction are pressed from the center of the convex shape toward both sides, and therefore, the excess thickness during forming is not retained in the flat surface portion, and is transferred in the direction of both sides and removed. Further, the press-forming operation is performed from the beginning to the end of the press-forming process. Therefore, the occurrence of wrinkles on the flat surface portion can be prevented and suppressed, and a high-precision flat surface shape can be formed. Therefore, other components can be mounted with high accuracy.

In the above embodiment, the structural member for a vehicle is a pillar provided at a side portion of the vehicle, and the reinforcing member is a hinge reinforcement for reinforcing the pillar. Therefore, the flat surface portion for attaching another component to the hinge reinforcement can be formed into a flat surface shape in which the occurrence of wrinkles is prevented and suppressed. Therefore, the structure of the pillar member reinforced by the hinge reinforcement can be made highly accurate.

In the above embodiment, the other vehicle component is a striker for locking a door of the vehicle, and the striker is attached to the flat surface portion. Therefore, the striker plane portion can be formed into a planar shape in which the occurrence of wrinkles is prevented and suppressed, and the striker can be mounted with high accuracy.

In the above embodiment, the reinforcing member is manufactured by press-forming using a press-forming die having a first die surface corresponding to the flat surface portion of the vertical wall portion and a second die surface corresponding to a portion of the vertical wall portion adjacent to the flat surface portion, the first die surface having a curved shape convex in the press direction than the second die surface. By press-forming the reinforcing member such as the hinge reinforcement member using the press-forming die having such a die face, the flat surface portion can be formed into a flat shape in which generation of wrinkles is prevented and suppressed.

In the above embodiment, the press forming is performed by a step of drawing the reinforcing member by a drawing die and a step of bending the drawn reinforcing member by a bending die, and the drawing die and the bending die each have the first die surface having the convex curved shape. By performing press forming using two dies, a drawing die and a bending die, it is possible to more reliably prevent and suppress the occurrence of wrinkles in the flat surface portion.

While the present invention has been described with reference to the specific embodiments, the present invention is not limited to these embodiments, and those skilled in the art can implement various substitutions, improvements, and modifications without departing from the object of the present invention.