Title of invention: Front pillar outer Technical field [0001] 　The present invention relates to a front pillar outer that constitutes a front pillar. Background technology [0002] 　A front pillar of a vehicle is configured by combining a front pillar inner and a front pillar outer. From the viewpoint of improving the fuel efficiency of automobiles, it is desirable that the front pillars forming the vehicle body be lightweight. On the other hand, it is desirable that the front pillar has high strength from the viewpoint of improving collision safety of the vehicle body. That is, the front pillar is required to be both lightweight and strong. [0003] 　Body parts having improved strength are described in, for example, Japanese Patent Application Laid-Open No. 2014-118090 (Patent Document 1), Japanese Patent Application Laid-Open No. 5-310147 (Patent Document 2), and Japanese Patent Application Laid-Open No. 2016-2781 (Patent Document 3). Has been done. [0004] 　Patent Literature 1 describes a front pillar lower including a reinforcing component. The reinforcing component described in Patent Document 1 includes a vertical surface portion facing the front wheel and a high-strength lateral surface portion. When the vehicle collides head-on, the front wheels move to the rear of the vehicle. The vertical surface portion restricts the movement of the front wheels toward the rear of the vehicle. The lateral surface portion absorbs collision energy applied to the vertical surface portion. It is described in Patent Document 1 that this makes it possible to suppress deformation of the front pillar lower due to a collision. [0005] 　The vehicle body component disclosed in Patent Document 2 includes a first structure having a closed cross section and a second structure having a closed cross section and welded to the first structure. Therefore, the vehicle body part includes a region configured by only the first structure and a region configured by the first structure and the second structure. That is, the vehicle body component includes two regions having different plate thicknesses. It is described in Patent Document 2 that this improves the ability of the vehicle body component to absorb the collision energy. [0006] 　The vehicle body component disclosed in Patent Document 3 includes a U-shaped first component and a U-shaped second component. Slits are provided at the ends of the first part and the second part, respectively. The slit of the first part overlaps the slit of the second part and is welded. Therefore, the strength of the two parts is increased because the two parts overlap each other. As a result, it is described in Patent Document 3 that the strength of the vehicle body component is high even without providing a reinforcing plate or the like as a separate member. [0007] 　In addition to Patent Documents 1 to 3, in order to satisfy both the weight reduction of the vehicle body and the improvement of the strength of the vehicle body, the material of the front pillar is tailored welded blank (hereinafter referred to as TWB) and tailored rolled blank (hereinafter referred to as TWB). , TRB)). It is also possible to attach a reinforcing plate to a part of the front pillar. [0008] 　TWB is a material obtained by combining and welding different materials or metal plates having different plate thicknesses. Parts manufactured by TWB have partially different board thicknesses, different strengths, or both. [0009] 　TRB is a material whose plate thickness changes continuously. Parts manufactured by TRB have partially different board thicknesses, different strengths, or both. Prior art documents Patent literature [0010] Patent Document 1: Japanese Patent Laid-Open No. 2014-11809 Patent Document 2: Japanese Patent Laid-Open No. 5-310147 Japanese Patent Document 3: Japanese Patent Laid-Open No. 2016-2781 Summary of the invention Problems to be Solved by the Invention [0011] 　However, the front pillar lower described in Patent Document 1 includes a reinforcing component that is a separate member. The vehicle body component described in Patent Document 2 includes a second structure that is welded to the first structure along the longitudinal direction of the first structure. In the vehicle body component described in Patent Document 3, the first component is welded to the second component over the entire cross section of the welded portion between the first component and the second component. Therefore, the weight of the vehicle body parts of Patent Documents 1 to 3 is heavy. [0012] 　In addition, the TWB is generally composed of two different metal plates. Therefore, the TWB has only two intensity regions. The same applies to the parts reinforced by the reinforcing plate. TRB has a high manufacturing cost. Furthermore, when a long component such as a front pillar outer is manufactured by TWB, TRB or a reinforcing plate, it is difficult to provide different strength regions in the direction (width direction) orthogonal to the longitudinal direction. [0013] 　An object of the present invention is to provide a front pillar outerwear that is lightweight and has high strength. Means for solving the problems [0014] 　The front pillar outer according to the present embodiment includes a glass surface side flange portion, a door side flange portion, and a main body portion connecting the glass surface side flange portion and the door side flange portion. The front pillar outer includes a first member and a second member. The first member extends from the front end of the front pillar outer to the rear end. The first member includes a first glass surface side flange portion that forms a part of the glass surface side flange portion, a first door side flange portion that forms a part of the door side flange portion, and a first glass surface side flange portion. And a first main body portion that connects the first door-side flange portion. The second member extends from the rear end of the front pillar outer toward the front end, and has a smaller plate thickness than the first member. The second member includes a second glass surface side flange portion that forms a part of the glass surface side flange portion, a second door side flange portion that forms a part of the door side flange portion, and a second glass surface side flange portion. And a second main body portion that connects the second door side flange portion. The first door-side flange portion projects toward the rear end of the front pillar outer than the first glass surface-side flange portion and the first body portion, and overlaps with the second door-side flange portion. The second glass surface side flange portion overlaps the rear region of the first glass surface side flange portion. The second body portion overlaps the rear region of the first body portion. A region where the first door side flange portion overlaps with the second door side flange portion, a region where the second glass surface side flange portion overlaps with the first glass surface side flange portion, and a second main body portion overlaps with the first main body portion. In the region, the first member is joined to the second member. Effect of the invention [0015] 　The front pillar outer according to the present invention is lightweight and has high strength. Brief description of the drawings [0016] FIG. 1 is a cross-sectional view of a front pillar. FIG. 2 is a perspective view of a front pillar outer. FIG. 3 is an exploded view of the front pillar outer shown in FIG. FIG. 4 is a perspective view showing a front pillar outer having a collision load applied thereto. FIG. 5 is a diagram showing a part of a vehicle body structure including a front pillar outer. FIG. 6 is a diagram showing analysis conditions of Example 1. FIG. 7 is a load-displacement diagram obtained from the results of Example 2. FIG. 8 is a maximum load-lightening rate diagram obtained from the results of Example 2. FIG. 9 is an exploded view of the front pillar outer whose flange portion on the first door side is shorter than the front pillar outer shown in FIG. 3. FIG. 10 is an exploded view of a front pillar outer having a first glass surface side flange portion that is longer than the front pillar outer shown in FIG. FIG. 11 is a diagram illustrating a method of calculating a weight reduction rate according to the second embodiment. MODE FOR CARRYING OUT THE INVENTION [0017] 　The front pillar outer according to the present embodiment includes a glass surface side flange portion, a door side flange portion, and a main body portion connecting the glass surface side flange portion and the door side flange portion. The front pillar outer includes a first member and a second member. The first member extends from the front end of the front pillar outer to the rear end. The first member includes a first glass surface side flange portion that forms a part of the glass surface side flange portion, a first door side flange portion that forms a part of the door side flange portion, and a first glass surface side flange portion. And a first main body portion that connects the first door-side flange portion. The second member extends from the rear end of the front pillar outer toward the front end, and has a smaller plate thickness than the first member. The second member includes a second glass surface side flange portion that forms a part of the glass surface side flange portion, a second door side flange portion that forms a part of the door side flange portion, and a second glass surface side flange portion. And a second main body portion that connects the second door side flange portion. The first door-side flange portion projects toward the rear end of the front pillar outer than the first glass surface-side flange portion and the first body portion, and overlaps with the second door-side flange portion. The second glass surface side flange portion overlaps the rear region of the first glass surface side flange portion. The second body portion overlaps the rear region of the first body portion. A region where the first door side flange portion overlaps with the second door side flange portion, a region where the second glass surface side flange portion overlaps with the first glass surface side flange portion, and a second main body portion overlaps with the first main body portion. In the region, the first member is joined to the second member. [0018] 　When a collision load is applied to the front pillar outer, the front pillar outer bends. When the front pillar outer is bent, a compressive stress is applied to the door side flange portion and a tensile stress is applied to the glass surface side flange portion. In the front pillar outer of the present embodiment, the first member overlaps and is joined to the second member in the region where the compressive stress is applied. This increases the strength of the front pillar outer. This is because the buckling resistance of the part where compressive stress is applied is influenced by the product of the material strength to the third power and the cube of the plate thickness. Is greatly improved. In the region where the tensile stress is applied, the front pillar outer is composed of only the second member having a smaller plate thickness than the first member. This reduces the weight of the front pillar outer. This is because the strength of the portion to which tensile stress is applied is influenced by the product of the material strength and the plate thickness. That is, the buckling resistance of the compressed portion is greatly improved by increasing the plate thickness (total plate thickness of the overlapping portion) rather than improving the material strength. On the other hand, in the region where the tensile stress is applied, the material strength and the plate thickness have substantially the same degree of influence, so from the viewpoint of weight reduction, it is better to increase the material strength than to increase the plate thickness. At the front part of the front pillar outer, there is a first member that is thicker than the second member, and constitutes the front pillar outer. As a result, the strength of the front part of the front pillar outer is high. In short, the front pillar outer of this embodiment includes three strength regions. Each of the three strength regions is provided in an appropriate region in the longitudinal direction and the width direction of the front pillar outer. This reduces the weight of the front pillar outer and increases the strength of the front pillar outer. [0019] 　In the above front pillar outer, when the length of the glass surface side flange portion is L, the area where the first door side flange portion overlaps with the second door side flange portion is the glass surface side flange portion in the door side flange portion. It is preferably provided in at least a part or the entire area of ​​L×2/3 from the position corresponding to the rear end. [0020] 　In many cases, when a collision load is applied to the front pillar outer, compressive stress is likely to be applied to the door side flange portion in the curved region near the rear end of the front pillar outer. Therefore, in this region, if the first member overlaps with the second member and is joined, buckling of the front pillar outer can be suppressed, and the strength of the front pillar outer increases. [0021] 　In the above front pillar outer, when the length of the glass surface side flange portion is L, the region where the second glass surface side flange portion overlaps with the first glass surface side flange portion is from the front end of the glass surface side flange portion. It is preferably provided in at least a part or the entire range of L×1/4 to L×2/3. [0022] 　As will be described later, when a collision load is applied to the front pillar outer, compressive stress may be applied to the glass surface side flange portion. Therefore, in this region, if the first member overlaps with the second member and is joined, buckling of the front pillar outer can be suppressed, and the strength of the front pillar outer increases. [0023] 　In the above front pillar outer, the plate thickness of the second member is preferably 0.60 mm or more and 1.60 mm or less. More preferably, the lower limit of the plate thickness of the second member is 0.85 mm or more. More preferably, the upper limit of the plate thickness of the second member is 1.05 mm or less. Further, the tensile strength of the first member and the second member is preferably 800 MPa or more. More preferably, the tensile strength of the first member and the second member is 1200 MPa or more. Further, the tensile strength of the second member is preferably higher than the tensile strength of the first member. [0024] 　The first member is preferably joined to the second member by laser welding, spot welding, mechanical fastening, an adhesive, or a combination of these joining methods. Further, the first member and the second member may be separately molded and then bonded, or may be bonded and molded in the state of the plate before molding. [0025] 　In this case, the front pillar outer is suitable as a front pillar outer for an automobile. [0026] 　In the present specification, "front", "rear", "left", "right", "upper" and "lower" mean "front", "rear", "left", "right", " Matches "top" and "bottom". Reference numerals “F”, “Re”, “Le”, “R”, “U” and “D” in the drawings mean front, rear, left, right, top and bottom of the vehicle, respectively. [0027] 　Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts will be denoted by the same reference symbols and description thereof will not be repeated. [0028] 　[Front Pillar 4] 　FIG. 1 is a sectional view of the front pillar 4 (of the developed structure) of the present embodiment. In the present specification, the “front pillar 4” means the front pillar upper that supports the windshield and constitutes the skeleton of the vehicle body. Therefore, the "front pillar outer 1" is a member that constitutes the front pillar upper. In addition, the “cross section” in the present specification means a cross section perpendicular to the longitudinal direction of the front pillar outer 1, and the “longitudinal direction” means the direction from the front end to the rear end of the front pillar outer 1. [0029] 　FIG. 1 shows a cross section of a left front pillar of a vehicle. 1 is a sectional view taken along the line II in FIG. 2 described later. However, in FIG. 2, only the front pillar outer 1 is shown for convenience of description. Referring to FIG. 1, the front pillar 4 includes a side panel 2, a front pillar inner 3, and a front pillar outer 1. The side panel 2 is arranged outside the front pillar inner 3 and the front pillar outer 1 of the vehicle. The side panel 2 and the front pillar inner 3 form a closed cross section. The front pillar outer 1 is arranged within a closed cross section formed by the side panel 2 and the front pillar inner 3. The front pillar outer 1 plays a role of reinforcing the front pillar 4. [0030] 　The glass surface side flange portion 19 of the front pillar outer 1 is joined to the side panel 2 and the front pillar inner 3 by welding or the like. In the present specification, the “glass surface side flange portion 19 2 ”means a region of the front pillar outer 1 that directly or indirectly supports the windshield 10 of the vehicle. The glass surface side flange portion 19 supports the windshield 10 of the vehicle together with the side panel 2 and the front pillar inner 3. The door side flange portion 20 is joined to the side panel 2 and the front pillar inner 3 by welding or the like. In the present specification, the “door side flange portion 20 ”means a region of the front pillar outer 1 that directly or indirectly faces the vehicle door 11. The door side flange portion 20 faces the vehicle door 11 together with the side panel 2 and the front pillar inner 3. The cross-sectional shape of the front pillar outer 1 is a hat shape. [0031] 　[Front Pillar Outer 1] 　FIG. 2 is a perspective view of the front pillar outer 1. As shown in FIG. 2, the front pillar outer 1 includes a glass surface side flange portion 19, a door side flange portion 20, and a main body portion 22. The body portion 22 is disposed between the glass surface side flange portion 19 and the door side flange portion 20 in the width direction of the front pillar outer 1, and connects the glass surface side flange portion 19 and the door side flange portion 20. [0032] 　FIG. 3 is an exploded view of the front pillar outer 1 shown in FIG. As shown in FIG. 3, the front pillar outer 1 of the present embodiment includes a first member 5 and a second member 6. [0033] 　[First Member 5] 　The first member 5 extends from the front end to the rear end of the front pillar outer 1. The material of the first member 5 is, for example, a steel plate. The first member 5 includes a first glass surface side flange portion 7, a first door side flange portion 8, and a first main body portion 9. [0034] 　The first glass surface side flange portion 7 is a region of the first member 5 that directly or indirectly supports the windshield 10 shown in FIG. 1. The first glass surface side flange portion 7 extends along the longitudinal direction from the front end 31 of the front pillar outer 1 to a range of a predetermined distance. The first glass surface side flange portion 7 does not extend to the rear end 32 of the front pillar outer 1, and the rear end 35 of the first glass surface side flange portion 7 is located in front of the rear end 32 of the front pillar outer 1. To position. That is, the first glass surface side flange portion 7 constitutes a part of the glass surface side flange portion 19 of the front pillar outer 1. In the present specification, “constituting a part of the glass surface side flange portion 19 ”means forming a part of the glass surface side flange portion 19 of the front pillar outer 1 in the longitudinal direction. The same applies to the door-side flange portion 20 and the main body portion 22 described below. [0035] 　The first door-side flange portion 8 is a region of the first member 5 that directly or indirectly faces the door 11 shown in FIG. 1. The front region of the first door side flange portion 8 extends upward and rearward from the lower end 33 of the front pillar outer 1. The rear region of the first door-side flange portion 8 is a region to be joined to the second door-side flange portion 13 of the second member 6 described later, and the rear end 34 of the first door-side flange portion 8 extends in the longitudinal direction. It extends to the rear end 32 of the front pillar outer 1. [0036] 　The first main body portion 9 is located between the first glass surface side flange portion 7 and the first door side flange portion 8 in the width direction of the front pillar outer 1. The first main body portion 9 connects the first glass surface side flange portion 7 and the first door side flange portion 8. The first main body portion 9 extends from the front end 31 and the lower end 33 of the front pillar outer 1 to the same predetermined distance range as the first glass surface side flange portion 7. The first main body portion 9 does not extend to the rear end 32 of the front pillar outer 1. That is, the first main body portion 9 constitutes a part of the main body portion 22 of the front pillar outer 1. [0037] 　[Second Member 6] 　The second member 6 extends forward from the rear end 32 of the front pillar outer 1. The material of the second member 6 is, for example, a steel plate. The second member 6 is thinner than the first member 5. The second member 6 includes a second glass surface side flange portion 12, a second door side flange portion 13, and a second main body portion 14. [0038] 　The second glass surface side flange portion 12 is an area of ​​the second member 6 that directly or indirectly supports the windshield 10 shown in FIG. 1. The second glass surface side flange portion 12 extends along the longitudinal direction from the rear end 32 of the front pillar outer 1 toward the front to a range of a predetermined distance. The second glass surface side flange portion 12 does not extend to the front end 31 of the front pillar outer 1 and the front end 42 of the second glass surface side flange portion 12 is between the rear end 32 and the front end 31 of the front pillar outer 1. Located in. The front end 42 of the second glass surface side flange portion 12 shown in FIG. 3 is positioned L×1/4 rearward from the front end 31 of the front pillar outer 1. That is, the second glass surface side flange portion 12 constitutes a part of the glass surface side flange portion 19 of the front pillar outer 1. [0039] 　The second door side flange portion 13 is a region of the second member 6 that directly or indirectly faces the door 11 shown in FIG. 1. The second door side flange portion 13 extends along the longitudinal direction from the rear end 32 of the front pillar outer 1 toward the front to a range of a predetermined distance. The length of the second door side flange portion 13 in the longitudinal direction is shorter than that of the second glass surface side flange portion 12, and the front end 43 of the second door side flange portion 13 is more than the front end 42 of the second glass surface side flange portion 12. Is also located behind. That is, the second door side flange portion 13 constitutes a part of the door side flange portion 20 of the front pillar outer 1. [0040] 　The second main body portion 14 is located between the second glass surface side flange portion 12 and the second door side flange portion 13 in the width direction of the front pillar outer 1. The second main body portion 14 connects the second glass surface side flange portion 12 and the second door side flange portion 13. The second main body portion 14 extends along the longitudinal direction from the rear end 32 of the front pillar outer 1 to a range of the same predetermined distance as that of the second door side flange portion 13. The second body portion 14 does not extend to the front end 31 of the front pillar outer 1. That is, the second main body portion 14 constitutes a part of the main body portion 22 of the front pillar outer 1. [0041] 　In short, the glass surface side flange portion 19 of the front pillar outer 1 is composed of the first glass surface side flange portion 7 and the second glass surface side flange portion 12. The door side flange portion 20 of the front pillar outer 1 is composed of a first door side flange portion 8 and a second door side flange portion 13. The main body 22 of the front pillar outer 1 is composed of a first main body 9 and a second main body 14. [0042] 　The front pillar outer 1 having such a configuration includes three strength regions (first strength region A, second strength region B, and third strength region C) having different strengths (plate thicknesses). [0043] 　[First Strength Region A] In the 　present specification, the “first strength region A” means a region where the first member 5 and the second member 6 overlap and are joined. The position where the first strength region A is provided will be described. [0044] 　As shown in FIG. 3, a part of the first door side flange portion 8 projects toward the rear end 32 of the front pillar outer 1 more than the first glass surface side flange portion 7 and the first main body portion 9. The protruding portion of the first door-side flange portion 8 overlaps and is joined to the second door-side flange portion 13. That is, the first strength region A is provided in a part of the door side flange portion 20 of the front pillar outer 1. [0045] 　The plate thickness of the first strength region A is the sum of the plate thickness of the first member 5 and the plate thickness of the second member 6, and thus is thicker than the other regions. Therefore, the intensity of the first intensity region A is higher than that of the other regions. [0046] 　FIG. 4 is a perspective view showing the front pillar outer 1 to which a collision load is applied. Referring to FIG. 4, in the assembled vehicle, the front end of front pillar outer 1 is arranged at a position lower than the rear end. When the vehicle collides head-on, the collision load P is applied to the front end of the front pillar outer 1. As shown in FIG. 2, the front pillar outer 1 has a shape that curves upward from the front end to the rear end. When the collision load P is applied from the front of the front pillar outer 1, stress concentrates on the curved portion of the front pillar outer 1, and the curved portion tends to bend upward. Therefore, when a collision load P is applied to the front pillar outer 1, a compressive stress is applied to the door side flange portion 20 and a tensile stress is applied to the glass surface side flange portion 19. [0047] 　When the compressive stress becomes excessively large, the front pillar outer 1 buckles and bends upward. When the front pillar outer 1 buckles, the collision energy absorption capability of the front pillar outer 1 is significantly reduced. Therefore, in order to increase the strength of the front pillar outer 1, it is necessary to suppress buckling of the front pillar outer 1. [0048] 　In order to suppress the buckling of the front pillar outer 1, it is effective to increase the strength of the region to which the compressive stress is applied. In the case of the front pillar outer 1, the most compressive stress is applied to a region where the curvature of the door side flange portion 20 is large, which is indicated by a region S in FIG. 1 when viewed in a sectional view and a region S in FIG. 2 when viewed in a perspective view. .. Therefore, the first strength region A, which has the highest strength among the three strength regions, is provided in the portion to which the compressive stress is applied, that is, the door side flange portion 20. As a result, the front pillar outer 1 is less likely to buckle, and the strength of the front pillar outer 1 is increased. [0049] 　The first strength region A is provided not only in a part of the door side flange portion 20 but also in a part of the glass surface side flange portion 19. As shown in FIG. 3, a portion (rear region 15) at a predetermined distance from the rear end 35 of the first glass surface side flange portion 7 is a portion at a predetermined distance from the front end 42 of the second glass surface side flange portion 12. Overlapping and joined. From another perspective, the following can be said. The front region of the second glass surface side flange portion 12 projects toward the front end 31 of the front pillar outer 1 more than the second door side flange portion 13 and the second main body portion 14. The protruding portion of the second glass surface side flange portion 12 overlaps and is joined to the first glass surface side flange portion 7. In addition, the portion of the second glass surface side flange portion 12 that is behind the protruding portion of the second glass surface side flange portion 12 by a predetermined distance is also joined to overlap with the first glass surface side flange portion 7. That is, the first strength region A is also provided in a part of the glass surface side flange portion 19 of the front pillar outer 1. [0050] 　The first strength region A is provided not only in a part of the door side flange part 20 and a part of the glass surface side flange part 19, but also in a part of the main body part 22. A portion (rear region 16) at a predetermined distance from the rear end 36 of the first main body portion 9 overlaps and is joined to a portion at a predetermined distance from the front end 44 of the second main body portion 14. That is, the first strength region A is also provided in a part of the main body portion 22 of the front pillar outer 1. [0051] 　The front region of the second glass surface side flange portion 12 is overlapped and joined to the rear region 15 of the first glass surface side flange portion 7. The front region of the second body portion 14 overlaps and is joined to the rear region 16 of the first body portion 9. That is, in addition to the door side flange portion 20, the glass surface side flange portion 19 and the main body portion 22 also have the first member 5 and the second member 6 overlapped and joined. As a result, the first member 5 is firmly fixed to the second member 6. Further, by this, the glass surface side flange portion 19 and the main body portion 22 can also be provided with the first strength region A. In addition, the 2nd glass surface side flange part 12 does not need to be joined to the front end of the 1st glass surface side flange part 7. The same applies to the joining of the second main body 14 and the first main body 9. [0052] 　As described later, depending on the shape of the front pillar outer 1, a compressive stress may be applied to the glass surface side flange portion 19. In this case, the strength of the front pillar outer 1 is further enhanced if the first strength region is provided in the region of the glass surface side flange portion 19 where the compressive stress is applied. [0053] 　[Second Strength Region B] In the 　present specification, the “second strength region B” means a region in which the front pillar outer 1 is composed of only the second member 6. The rear region of the second glass surface side flange portion 12 does not overlap with the first member 5. The rear region of the second body portion 14 does not overlap with the first member 5. That is, the second strength region B is provided in a part (rear region) of the glass surface side flange portion 19 and a part (rear region) of the main body portion 22. As described above, the plate thickness of the second member 6 is thinner than that of the first member 5. Therefore, the weight of the front pillar outer 1 including the second strength region B is lighter than that of the front pillar outer 1 in which the entire area of ​​the second member 6 overlaps and is joined to the first member 5. [0054] 　As described above, the buckling resistance of the front pillar outer depends largely on the compressive stress. Therefore, the strength of the region where the tensile stress is applied can be lower than that of the region where the compressive stress is applied. In the case of the front pillar outer 1, tensile stress is applied to the glass surface side flange portion 19. That is, the strength of the glass surface side flange portion 19 can be made lower than the strength of the door side flange portion 20. Therefore, the second strength region B is provided in a part of the glass surface side flange portion 19. Further, the second strength region B is also provided in a part of the main body 22 to which a lower stress is applied than the glass surface side flange portion 19 and the door side flange portion 20. [0055] 　[Third Strength Region C] In the 　present specification, the “third strength region C” means a region in which the front pillar outer 1 is composed of only the first member 5. When the vehicle collides head-on, a collision load is applied to the front end 31 of the front pillar outer 1. Therefore, it is desirable that the strength of the front pillar outer 1 from the front end 31 to the first strength region A, that is, the third strength region C is high, and the plate thickness thereof is thick. Therefore, in the third strength region C, which is the front portion of the front pillar outer 1, there is the first member 5 having a higher strength and a larger plate thickness than the second member 6. [0056] 　As described above, the front pillar outer 1 of this embodiment includes two members, the first member 5 and the second member 6. In the region where the compressive stress is applied, the first member 5 and the second member 6 overlap and are joined (first strength region A). As a result, the strength of the front pillar outer 1 is increased. In the region in which the tensile stress is applied, the front pillar outer 1 is composed of only the second member 6 having a smaller plate thickness than the first member 5 (second strength region B). As a result, the weight of the front pillar outer 1 is reduced. At the front part of the front pillar outer 1, there is a first member 5 having a plate thickness thicker than that of the second member 6, and constitutes the front pillar outer 1 (third strength region C). As a result, the strength of the front portion of the front pillar outer 1 is high. In short, the front pillar outer 1 of this embodiment includes three strength regions. Each of the three strength regions is provided in an appropriate region in the longitudinal direction and the width direction of the front pillar outer 1. The “width direction” in the present embodiment means a direction orthogonal to the longitudinal direction and extending from the glass surface side flange portion 19 of the front pillar outer 1 toward the door side flange portion 20. As a result, the weight of the front pillar outer 1 is reduced and the strength of the front pillar outer 1 is increased. Further, this developed structure can give the member a strength region higher than that of the material used. [0057] 　Further, the front pillar outer 1 of the present embodiment is particularly effective in a local collision (small overlap) in a region on the left side or the right side of the front side member of the vehicle. [0058] 　Next, a preferable aspect of the front pillar outer 1 of the present embodiment will be described. [0059] 　[Range of First Strength Region A of Door Side Flange Portion 20] 　FIG. 5 is a diagram showing a part of the vehicle body structure including the front pillar outer 1. In FIG. 5, the side panel of the front pillar is omitted. Referring to FIG. 5, the rear end of the front pillar is joined to the roof 17 of the vehicle. The roof 17 of the vehicle is provided approximately horizontal to the ground. On the other hand, the windshield 10 of the vehicle is arranged obliquely with respect to the ground. Therefore, the front pillar is curved near the rear end. Along with this, the front pillar outer 1 also curves near the rear end. [0060] 　The load applied to the front pillar and the first strength region A will be described with reference to the drawings. When a collision load is applied to the front pillar outer 1, as shown in FIG. 4, compressive stress is likely to be applied to the door side flange portion 20 in the curved region S near the rear end of the front pillar outer 1. The shape of the front pillar outer 1 differs depending on the vehicle model. However, in many cases, as shown in FIG. 5, the compressive stress is partially or entirely in the range from L1 to L×2/3 corresponding to the rear end 21 of the glass surface side flange portion 19 in the door side flange portion 20. Is loaded. Here, L means the arc length (length in the longitudinal direction) along the edge of the glass surface side flange portion 19 of the front pillar outer 1 on the door side. [0061] 　Therefore, the first strength region A is provided in at least a part of the range from the position R1 to L×2/3 corresponding to the rear end 21 of the glass surface side flange portion 19 in the door side flange portion 20 of the front pillar outer 1. Preferably. [0062] 　More preferably, the first strength region A is L×2/3 from the position R1 corresponding to the rear end 21 of the glass surface side flange portion 19 in the door side flange portion 20 of the front pillar outer 1 as shown in FIG. It is provided in the entire range of. In this case, the rear end 34 of the first door side flange portion 8 extends to the rear end 32 of the front pillar outer 1. In other words, when viewed from above, the rear end 34 of the first door side flange portion 8 overlaps the rear end 32 of the front pillar outer 1. [0063] 　The range of the first strength region A of the door side flange portion 20 is not limited to this, and may be provided in the following range. [0064] 　FIG. 9 is an exploded view of the front pillar outer 1 in which the first door side flange portion 8 is shorter than the front pillar outer 1 shown in FIG. In the front pillar outer 1 shown in FIG. 9, the rear end 34 of the first door side flange portion 8 is located forward from the rear end 32 of the front pillar outer 1 by L×1/3. In other words, in the front pillar outer 1 shown in FIG. 9, the rear end 34 of the first door side flange portion 8 is located behind the front end 31 of the front pillar outer 1 by L×2/3. Further, the front end 42 of the second glass surface side flange portion 12 is positioned L×1/4 rearward from the front end 31 of the front pillar outer 1. [0065] 　In such a front pillar outer 1 of FIG. 9, the first door side flange portion 8 is shorter than the front pillar outer 1 shown in FIG. Accordingly, the range of the first strength region A in the door side flange portion 20 becomes narrower than that of the front pillar outer 1 shown in FIG. However, even with the front pillar outer 1 of FIG. 9, since the first strength region A is provided in the region where compressive stress is applied, the weight is reduced while maintaining the high strength of the front pillar outer 1. be able to. [0066] 　[Range of First Strength Region A of Glass Side Flange 19] 　FIG. 10 is an exploded view of the front pillar outer 1 in which the first glass side flange 7 is longer than the front pillar outer 1 shown in FIG. .. In the front pillar outer 1 shown in FIG. 10, the rear end 35 of the first glass surface side flange portion 7 is located rearward from the front end 31 of the front pillar outer 1 by L×2/3 or more. Further, the front end 42 of the second glass surface side flange portion 12 is located L×1/4 rearward from the front end 31 of the front pillar outer 1. That is, in the front pillar outer 1 shown in FIG. 10, in the glass surface side flange portion 19, the first strength region A is from the front end 31 of the front pillar outer 1 to the position L×1/4 to the position L×2/3. It is provided in the entire range of. [0067] 　When a collision load is applied to the front pillar outer 1, a compressive stress may be applied to the glass surface side flange portion 19. More specifically, the compressive load may be applied in a part or the whole area of ​​L×2/3 from the front end of the glass surface side flange portion 19 (the front end 31 of the front pillar outer 1). [0068] 　According to the front pillar outer 1 shown in FIG. 10, the first glass surface side flange portion 7 is longer than the front pillar outer 1 shown in FIG. Therefore, the range of the first strength region A in the glass surface side flange portion 19 becomes wider than that of the front pillar outer 1 shown in FIG. Therefore, the strength of the glass surface side flange portion 19 is further increased, and even when the glass surface side flange portion 19 is subjected to compressive stress, high buckling resistance can be exhibited. [0069] 　[ 　Plate Thickness] The plate thickness of the second member 6 is preferably 0.60 mm or more and 1.60 mm or less. If the plate thickness of the second member 6 is less than 0.60 mm, the strength of the second member 6 becomes too low. Therefore, it is difficult to sufficiently secure the strength of the second strength region B. Therefore, the lower limit of the plate thickness of the second member 6 is preferably 0.60 mm or more. If the plate thickness of the second member 6 is thicker than 1.60 mm, the weight of the second member 6 becomes too heavy. Therefore, the upper limit of the plate thickness of the second member 6 is preferably 1.60 mm. Further, more preferably, the lower limit of the plate thickness of the second member 6 is 0.85 mm or more based on Example 2 described later. More preferably, the upper limit of the plate thickness of the second member 6 is 1.05 mm or less based on Example 2 described later. However, the above range of plate thickness indicates a preferable range. Therefore, the weight of the front pillar outer 1 can be reduced and the strength thereof can be improved even if the thickness exceeds the above range. [0070] 　The plate thickness of the first member 5 may be thicker than the plate thickness of the second member 6, and is not particularly limited. For example, in the case of a front pillar for an automobile, the plate thickness of the first member 5 is preferably 1.2 mm or more and 1.5 mm or less. The ratio of the plate thickness of the second member 6 to the plate thickness of the first member 5 (plate thickness of the second member 6/plate thickness of the first member 5) is less than 1. The lower limit need not be specified, but may be 0.5, 0.6, or 0.7. The upper limit may be 0.9, 0.8 or 0.75. [0071] 　Further, when the object of the present invention to provide the front pillar outer 1 that is lightweight and has high strength is achieved, the weight reduction ratio described below becomes greater than 0%. That is, when the object of the present invention is achieved, the area from the front end of the second member 6 (the front end 42 of the second glass surface side flange portion 12) to the rear end 32 of the front pillar outer 1 is set as the evaluation area. When the area ratio of the second strength region B to the total area of ​​the region is b, the area ratio of the third strength region C is c, the plate thickness of the first member 5 is t1, and the plate thickness of the second member 6 is t2. , The following formula is satisfied. 　c-(t2/t1)×(1-b)>0 　where 01) times thicker than t1, the weight reduction rate is obtained by the following formula. .. 　Weight reduction rate (%) = (Comparative Example - Invention Example) / Comparative Example = 100 × (α × t1 × 1- (t2 × b + (t1 + t2) × a + t1 × c)) / (α × t1 × 1) 　where Since a+b+c=1 (where 0