WO2012090042A1

WO2012090042A1 - Vehicle structural part

Info

Publication number: WO2012090042A1
Application number: PCT/IB2011/003052
Authority: WO
Inventors: Takeo Mori
Original assignee: Toyota Jidosha Kabushiki Kaisha
Priority date: 2010-12-27
Filing date: 2011-12-15
Publication date: 2012-07-05
Also published as: JP2012136190A

Abstract

A vehicle structural part has an outer member (21), an inner member (22), and a reinforcing member (24; 124; 224; 324; 424) that is disposed between the outer member (21) and the inner members (22), and that has a center flange portions (32) at front and rear sides thereof in a vehicle longitudinal direction. A central portion of the reinforcing member located between the two center flange portions (32) disposed in a vehicle outer side of the center flange portions (32). The reinforcing member (24; 124; 224; 324; 424) has a projection portion that is formed such that, from an upper side toward a lower side in the vertical direction, a distance in the vehicle width direction between an end portion in the outer side and an end portion in the inner side of the projection portion increases, becomes maximum near a beltline, and then decreases.

Description

VEHICLE STRUCTURAL PART

BACKGROUND OF THE INVENTION

1. Field of the Invention

[0001] The invention relates to a structural part for a vehicle.

2. Description of Related Art

[0002] A technology of a pillar for a vehicle which is equipped with a reinforcing member is known. For example, Japanese Patent Application Publication No. .2004-314845 (JP-A-2004-314845)^' describes a center pillar structure of a vehicle which includes an outer member, an inner member that is coupled to the outer member at two opposite end portions thereof in a vehicle longitudinal direction, and a reinforcing member that is disposed between the outer member and the inner member and that is coupled to the outer member and the inner member at two opposite end portions thereof in the vehicle longitudinal direction. Besides, this publication also describes that in the center pillar structure, an intermediate portion of the reinforcing member in the -vehicle longitudinal direction is provided with at least one wall portion that has an extension portion that extends in a vehicle inside/outside direction beyond the two end portions of the reinforcing member in the vehicle longitudinal direction.

[0003] As described in the foregoing Japanese Patent Application Publication No. 2004-314845 (JP-A-2004-314845), the provision of the reinforcing member makes it possible to improve the strength of the center pillar and to. increase the deformation resistance to side-collision load. Besides, since the deformation resistance to side-collision load can be increased by a structure of a single reinforcing member, the center pillar can be reduced in weight. However, even in the case where a vehicle is_. provided with a reinforcing member that has a shape or configuration that is described in the foregoing publication, if a side-collision load acts on the center pillar, there is a possibility that the center pillar may buckle and there is also a possibility of occurrence of buckling of the center pillar at a not-intended position. If a reinforcing member is disposed as an added member in order to reduce the aforementioned possibilities, the weight of the center pillar increases.

SUMMARY OF THE INVENTION

[0004] The invention provides a structural part for a vehicle which is less apt to buckle when receiving side-collision load, and which is light in weight.

[0005] A first aspect of the invention relates to a vehicle structural part that includes: an outer member that extends in a vertical direction of a vehicle, that has outer flange portions at a front side and a rear side of the outer member in a longitudinal direction of the vehicle, and that has a portion between the outer flange portion at the front side and the outer flange portion at the rear side projection from the outer flange portions to an outer side relative to the vehicle in a vehicle width direction; an inner member that extends in the vertical direction, that has, at the front side and the rear side of the inner member in the longitudinal direction, inner flange portions that engage with the outer flange portions of the outer member respectively, and that is disposed in an inner side of the outer member relative to the vehicle in the vehicle width direction; and a reinforcing member that is disposed between the outer member and the inner member, that has center flange portions at the front side and the rear side of the reinforcing member in the longitudinal direction of the vehicle, and that has a central portion that is located between the two center flange portions disposed in the outer side of the center flange portions relative to the vehicle. The reinforcing member has a projection portion that is formed such that, from an upper side toward a lower side in the vertical direction, a distance in the vehicle width direction between an end portion in the outer side and an end portion in the inner side of the projection portion increases, becomes maximum near a beltline, and then decreases.

[0006] In the foregoing aspect, an upper-side end portion of the projection portion in the vertical direction may be to the upper side of an upper-side end portion of a seatbelt anchor of the vehicle.

[0007] In the foregoing aspect, an upper-side end portion of the projection portion in the vertical direction may .be in proximity of an upper-side end portion of a seatbelt anchor.

[0008] In the foregoing aspect, a lower-side end portion of the projection portion in the vertical direction may be to the lower side of an upper end of a door hinge of the vehicle.

[0009 j In the foregoing aspect, a lower-side end portion of the projection portion in the vertical direction may be in proximity of an upper end of a door hinge of the vehicle.

[0010] In the foregoing aspect, the projection portion may include a protrusion portion that is provided in proximity of a center of the reinforcing member in the longitudinal direction, and that is projection to the outer side relative to the vehicle.

[0011] In the foregoing aspect, the projection portion may include a plurality of the protrusion portions, and the protrusion portions may be linked together in the longitudinal direction.

[0012] In the foregoing aspect, the projection portion may include a depression portion that is provided in proximity of a center of the reinforcing member in the longitudinal direction, and that is projection to the inner side relative to the vehicle.

[0013] In the foregoing aspect, the projection portion may include an end-side depression portion that is provided in proximity of at least one of end portions of the reinforcing member in the longitudinal direction, and that is projection to the inner side relative to the vehicle.

[0014] In the foregoing aspect, the center flange may be engaged between the outer flange and the inner flange.

[0015] _. A second aspect of the invention relates to a vehicle structural part that has: an outer member extending in a vertical direction of a vehicle; an inner member extending in the vertical direction of the vehicle; and a reinforcing member held between the outer member and the inner member. A height of a protrusion portion provided in the reinforcing member or a depth of a depression portion provided in the reinforcing member is maximum in proximity of a beltline, and the height of the protrusion portion or the depth of the. depression portion decreases from, the beltlin toward an upper side or a lower side.

[0016] A third aspect of the invention relates to a vehicle structural part that has: an outer member extending in a vertical direction of a vehicle; an inner member extending in the vertical direction of the vehicle; and a reinforcing member held between the outer member and the inner member. An amount of processing of a protrusion portion provided in the reinforcing member or a depression portion provided in the reinforcing member is maximum in proximity of a beltline, and the amount of processing of the depression portion or the protrusion portion decreases from the beltline toward an upper side or a lower side.

[0017] In the foregoing aspect, the vehicle structural part may be provided in a center pillar.

[0018] In the vehicle structural parts in accordance with the foregoing aspects, because the reinforcing member is provided with a projection (protrusion/depression) portion in which the distance between a protrusion and a depression in the vehicle width direction gradually changes, and becomes maximum at the beltline, it is possible to attain an appropriate strength in the vertical direction of the vehicle, and restrain local concentration of strain, and make the buckling of the structural part less likely to occur when the structural part receives side-collision load. Besides, since the structural part can be made less apt to buckle by adjusting the shape of a single reinforcing member, it is possible to restrain increase in the number of component members, and to reduce the weight of the structural part.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Features, advantages, and technical and industrial significance of exemplary embodiments of the invention will be described below with reference to the accompanying drawings, in which like numerals denote like elements, and wherein:

FIG. 1 is a side view of a vehicle that has a vehicular center pillar in accordance with a first embodiment of the invention;

FIG. 2. i s a is a front view -of a center, pillar, in .accordance , with the first embodiment; FIG. 3 is a sectional view taken along a line A- A in FIG. 2;

FIG. 4 is a sectional view taken along a line B-B in FIG. 2;

FIG. 5 is a sectional view taken along a line C-C in FIG. 2;

FIG. 6 is an illustrative diagram showing a distribution of force that acts on the center pillar shown in FIG. 4 when the pillar receives side-collision load;

FIG. 7 is a front view of a center pillar in accordance with a second embodiment of the invention;

FIG. 8 is a sectional view of a center pillar shown in FIG. 7;

FIG. 9 is a front view of a center pillar in accordance with a third embodiment of the invention;

FIG. 10 is a sectional view of the center pillar shown in FIG. 9;

FIG. 11 is an illustrative diagram showing a distribution of force that acts on the center pillar shown in FIG. 10 when the pillar receives side-collision load;

FIG. 12 is a front view of a center pillar in accordance with a fourth embodiment of the invention;

FIG. 13 is a sectional view of the center pillar shown in FIG. 12;

FIG. 14 is a front view of a center pillar in accordance with a fifth embodiment of invention; and

FIG. 15 is a sectional view of the center pillar shown in FIG. 14.

DETAILED DESCRIPTION OF EMBODIMENTS

[0020] Hereinafter, embodiments of the vehicle structural part of the invention will be described in detail with reference to the drawings. Incidentally, the embodiments do not limit the invention. Besides, the component elements of the embodiments below include technologies that a person having ordinary skill in the art can easily conceive, or component elements that are substantially the same as those technologies.

[0021] Hereinafter, with reference to FIG. 1 to FIG. 6, a vehicle center pillar as a structural part for a vehicle in accordance with . a. first . embodiment of the. invention will ,

6

be described. FIG. 1 is a side view of a vehicle that has a vehicle center pillar in accordance with the first embodiment. FIG 2 is a front view of the center pillar in accordance with the first embodiment. FIG. 3 is a sectional view taken along a line A- A in FIG. 2, and FIG 4 is a sectional view taken along a line B-B, and FIG. 5 is a sectional view taken along a line C-C in FIG. 2. FIG. 6 is an illustrative diagram showing a distribution of force that acts on the center pillar shown in FIG. 4 when the pillar receives side-collision load.

[0022] Incidentally, in the following description, the direction along the traveling direction of a vehicle 1 is referred to as vehicle longitudinal direction (also referred to simply as "longitudinal direction"), and the direction of the height of the vehicle. 1 will be referred to as vehicle vertical direction (also referred to simply as "vertical direction"), and the direction orthogonal to the vehicle longitudinal direction and to the vehicle vertical direction will be referred to as vehicle width direction, unless otherwise indicated. Typically, during a state in which wheels of the vehicle 1 are on a flat road surface, the vehicle vertical direction is a direction along the vertical direction, and the vehicle longitudinal direction and the vehicle width direction are directions along the horizontal direction. Besides, a side of a space within the vehicle 1 in which a cabin of the vehicle 1 is defined will be referred to as inner side relative to the cabin* and a side of the external air outside the vehicle will be referred to as outer side relative to the cabin.

[0023] As shown in FIG. 1, the vehicle 1 includes a front pillar (A pillar) 3, a center pillar (B pillar) 4, a rear pillar (C pillar) 5, a roof side rail 6, rocker 7, etc. on at least one of right and left sides of the vehicle 1 as high-strength and high-rigidity vehicle body framework component parts that constitute a framework of a vehicle body 2. Besides, in the vehicle 1, a door that includes a window 13 and a side panel 14 is disposed between the front pillar 3 and the center pillar 4 of a front side portion 8 that corresponds to a side face of the vehicle body 2. Besides, in the vehicle vertical direction, the window 13 is disposed at an upper side of the side panel 14, and a boundary 15 is provided between the window 13 and the side panel 14. Besides, a door hinge 17 for . linking another door,. and a.seatbelt anchor 18 . that supports .a slip joint of . a seatbelt are linked to the center pillar 4. Incidentally, the door hinge 17 links the center pillar 4 and the door disposed between the center pillar 4 and the rear pillar 5 (a rear-side door in the vehicle longitudinal direction).

[0024] The front pillar 3, the center pillar 4 and the rear pillar 5 are supporting post members, and extend in the vehicle body side portion 8 of the vehicle 1 in the vehicle vertical direction, that is, the vertical direction. The front pillar 3 is disposed in a front portion of the vehicle body side portion 8 in the vehicle longitudinal direction, and the center pillar 4 is disposed in an intermediate portion of the vehicle body side portion 8 in the vehicle longitudinal direction, and the rear pillar 5 is disposed in a rear portion of the vehicle body side portion 8 in the vehicle longitudinal direction. The roof side rail 6 and the rocker 7 are beam members, and extend in the vehicle body side portion 8 in the vehicle longitudinal direction, that is, a horizontal direction. The roof side rail 6 is disposed in an upper portion of the vehicle body side portion 8 in the vehicle vertical direction, and the rocker 7 is disposed in a lower portion of the vehicle body side portion 8 in the vehicle vertical direction. The front pillar 3, the center pillar 4 and the rear pillar 5 are linked together by the roof side rail 6 and the rocker 7 so as to form a framework of the vehicle body 2. Incidentally, the first embodiment will be described in conjunction with a construction in which the vehicle structural part of the invention is applied to the center pillar 4, but the vehicle structural part of the invention is not limited so. It suffices that the vehicle structural part of the invention is a structural part that constitutes the vehicle body 2 of the vehicle 1 ; for example, the vehicle structural part may be applied to the front pillar '3 or the rear pillar 5 as well.

[0025] Next, the center pillar 4 will be described in detail.

[0026] In the following description, the inner side relative to the cabin in the vehicle width direction will be simply termed the "inner side", and the outer side relative to the cabin in the vehicle width direction will be simply termed the "outer side". Besides, the upper side in the vehicle vertical direction of the vehicle 1 will be simply termed the "upper side", and the lower side in the vehicle vertical direction will be simply termed the "lower, side".. ...Besides, the front side in the vehicle longitudinal. direction of the vehicle 1 will be simply termed the "front side", and the rear side in the vehicle longitudinal direction will be simply termed the "rear side". The center pillar 4, as shown in FIGS. 1 to 5, is a member that separates the inside and the outside of the vehicle 1, and is formed substantially along the vehicle vertical direction, that is, substantially along the vertical direction. As for the center pillar 4, an upper end portion thereof in the vehicle vertical direction is coupled to the roof side rail 6, and a lower end portion thereof is coupled to the rocker 7. As shown in FIG. 1 and FIG. 5, the center pillar 4 has a center pillar outer part (a side member outer panel, or an outer member) 21 , a center pillar inner part (inner member) 22, and an outer reinforcement (reinforcing member) 24. Incidentally, in FIG. 2, illustration of the side member outer panel (center pillar outer part) 21 is omitted.

[0027] The center pillar outer part 21 and the center pillar inner part 22 are pillar main parts of the center pillar 4. The center pillar outer part 21 and the center pillar inner part 22 extend in the vehicle vertical direction. Front and rear sides of the center pillar outer part 21 are provided with flange portions 34 (outer flanges). The center pillar outer part 21 has a projection portion that is protruded to the outer side between the flange portion 34 provided on the front side and the flange portion 34 provided on the rear side. Thus, the center pillar outer part 21 is formed so that the shape of a cross-section thereof orthogonal to the extending direction of the center pillar 4 is a shape that is protruded to the Outer side.

[0028] The front and rear sides of the center pillar inner part 22 are provided with flange portions 30 (inner flanges). The center pillar inner part 22 has a projection portion that is protruded to the inner side between the flange portion 30 provided on the front side and the flange portion 30 provided on the rear side. Thus, the center pillar inner part 22 is formed so that the shape of a cross-section thereof orthogonal to the extending direction of the center pillar 4 is a shape that is protruded to the inner side.

[0029] The center pillar inner part 22 changes in its sectional shape depending on the position in the vehicle vertical direction as shown in FIGS. 2 to 5. Concretely, as shown. in FIG. A, an intermediate . ortion of the center, pillar. 4. in -the ..vehicle vertical direction is provided with a protrusion surface 22a that is protruded to the outer side. That is, the center pillar inner part 22 is provided with the protrusion surface 22a that is protruded more to the outer side than a reference surface 22b in a cross-section taken on the line B-B. Besides, the protrusion surface 22a is formed in a region that includes the center of the center pillar inner part 2 in the vehicle longitudinal direction. Reference surfaces 22b are disposed on the front and rear sides of the protrusion surface 22a in the vehicle longitudinal direction. That is, end portions of the protrusion surface 22a in the vehicle longitudinal direction are respectively linked to the reference surfaces 22b. An end portion of each of the two reference surfaces 22b that is to the side of the center of the center pillar inner part 22 in the vehicle longitudinal direction is linked to the protrusion surface 22a, and an end portion of each reference surface 22b that is remote from the center of the center pillar inner part 22 in the vehicle longitudinal direction is linked to an adjacent one of the flange portions 30. In the region in which the protrusion surface 22a is formed, the distance between the protrusion surface 22a and the reference surfaces 22b (the distance therebetween in the vehicle width direction) gradually increases (becomes longer) and then gradually reduces (becomes shorter) with increase in the distance from an upper end of the region toward a lower end portion thereof in the vehicle vertical direction. That is, as shown in FIG. 2, the protrusion surface 22a has such a shape as to gradually become apart from the reference surfaces 22b and then gradually approach the reference surfaces 22b. In the center pillar inner part 22, the distance between the protrusion surface 22a and the reference surfaces 22b becomes maximum in the vicinity of a beltline (not shown). The beltline herein means, in the case of a passenger automobile, a position of the height of a belt of a human occupant, for example, the vicinity of a portion of the center pillar 4 that sharply bends, the vicinity of a portion of the center pillar 4 that is a lower end portion of the exposed region of the window 13 and that sharply bends, or the vicinity of the boundary 15.

[0030] The outer reinforcement 24 functions as a reinforcing member that connects the front-side flange portions and the rear-side flange portions of the pillar main parts... A . front . side., and a rear side. of -.the .outer reinforcement..24 are respectively provided with flange portions 32 (center flanges). The outer reinforcement 24 is provided with a projection portion that is protruded to the outer side, between the flange portion 32 provided on the front side and the flange portion 32 provided on the rear side. Thus, the outer reinforcement 24 is basically formed so that the shape of a cross-section thereof orthogonal to the extending direction of the center pillar 4 is a shape that is protruded to the outer side.

[0031] Next, the projection portion of the outer reinforcement 24 will be described. The cross-sectional shape of the outer reinforcement 24 changes depending on the position in the vehicle vertical direction as shown in FIGS. 2 to 5. Concretely, as shown in FIG. 4, an intermediate portion of the center pillar 4 in the vehicle vertical direction is provided with a protrusion/depression portion that is made up of a first protrusion surface 24a, second protrusion surfaces 24b and reference surfaces 24c that are protruded to the outer side. Concretely, the outer reinforcement 24 is formed so that a cross-section of the projection portion taken along the line B-B in FIG. 2 includes the second protrusion surfaces 24b that are protruded more to the outer side than the reference surfaces 24c, and the first protrusion surface 24a that is protruded more to the outer side than the second protrusion surfaces 24b.

[0032] The first protrusion surface 24a is formed in a region that includes the center of the outer reinforcement 24 in the vehicle longitudinal direction. The second protrusion surfaces 24b are disposed on sides of the first protrusion surface 24a which are apart from the center of the outer reinforcement 24 in the vehicle longitudinal direction. The reference surfaces 24c are disposed on sides of the second protrusion surfaces 24b which are apart from the center of the outer reinforcement 24 in the vehicle longitudinal direction. That is, the two opposite ends of the first protrusion surface 24a in the vehicle longitudinal direction are respectively linked to the second protrusion surfaces 24b. In each of the two second protrusion surfaces 24b, an end portion thereof toward the center of the outer reinforcement 24 in the vehicle longitudinal direction is linked to the first protrusion surface 24a, and an end portion thereof remote from the center is linked to an adjacent one of the reference surfaces 24a.... In each, of the two reference -surfaces 24c, an end portion thereof toward the center in the vehicle longitudinal direction is linked to an adjacent one of the second protrusion surfaces 24b, and an end portion thereof remote from the center is linked to an adjacent one of the flange portions 32. Thus, the protrusion/depression portion has an arrangement in which the flange portions 32, the reference surfaces 24c, the second protrusion surfaces 24b and the first protrusion surface 24a are disposed in that order from the two opposite end portions to the center of the outer reinforcement 24 in the vehicle longitudinal direction. Thus, protrusions and depressions in a stepwise arrangement are formed so as to be more protruded to the outer side with increase in the distance from the opposite end portions toward the center of the outer reinforcement 24 in the vehicle longitudinal direction.

[0033] It is to be noted herein that in the region where the first protrusion surface 24a and the second protrusion surfaces 24b are formed, the distances between the first protrusion surface 24a and the reference surfaces 24c (the distances therebetween in the vehicle width direction) and the distances between the second protrusion surfaces 24b and the reference surfaces 24c (the distances therebetween in the vehicle width direction) gradually increase and then gradually decrease with increase in the distance from the upper end of the region toward the lower end thereof in the vehicle vertical direction. That is, as shown in FIG. 2, the first protrusion surface 24a and the second protrusion surfaces 24b have such a shape as to become gradually further apart from the reference surfaces 24c and then become gradually closer to the reference surfaces 24c. In the outer reinforcement 24, the distance between the first protrusion surface 24a and the reference surfaces 24c and the distance between the second protrusion surfaces 24b and the reference surfaces 24c become maximum in the vicinity of the beltline. That is, in the vicinity of the beltline, there is a site where the amount of processing of the outer reinforcement 24 becomes maximum and the maximum rigidity is retained. The amount of processing herein means an amount of elongation (amount of deformation) that is obtained in that regio'n when the outer reinforcement is produced by deforming a platy member. Besides, the distance between the first protrusion surface 24a and the reference surfaces.24c : and the . distance -between the- second, protrusion, surfaces 24b and the reference surfaces 24c change proportionally to each other. That is, the amount of processing of the outer reinforcement 24 decreases and the rigidity thereof decreases gradually with increase in the distance from the upper end toward, the lower end in the vehicle vertical direction.

[0034] Next, the flange portions are orthogonal to the vehicle width direction, and are parallel to each other. That is, the front-side flange portions 30, 32 and 34 are orthogonal to the vehicle with direction, and face each other in the vehicle width direction. Besides, the rear-side flange portions 30, 32 and 34 are orthogonal to the vehicle with direction, and face each other in the vehicle width direction. The flange portions 30, the flange portions 32 and the flange portion2 34 that face each other are linked to (engaged with) each other by welding, screwing, etc.

[0035] As for the center pillar 4 of the vehicle 1 , the shape of the outer reinforcement 24 in the vicinity of the beltline is a shape in which a portion toward the center of the outer reinforcement 24 in the vehicle longitudinal direction is more protruded to the outer side. Therefore, there is obtained a shape in which a central portion in the vehicle longitudinal direction is more bulged to the outer side. As shown in FIG. 6, the distribution of load in the vehicle longitudinal direction when side-collision load acts can be made more uniform. That is, due to the shape in which a center-side portion in the vehicle longitudinal direction where load is more likely to act is more protruded to the outer side, the center and its proximity in the vehicle longitudinal direction can be restrained from undergoing elastic buckling, so that the load distribution as a whole can be made more uniform. Besides, because the shape of the center pillar inner part 22 in the vicinity of the beltline is a shape in which the center-side portion in the vehicle longitudinal direction is a shape that is protruded to the outer side, the distribution of the load related to the center pillar inner part 22 can also be more uniform.

[0036] Because the shape of the protrusion/depression portion is gradually changed so that the height difference between the protrusions and the depressions becomes maximum in the vicinity of the beltline as shown in FIG. 2, the distribution of , the flexural. strength- of a . cross_^section in. the vehicle vertical, direction can be made such that the flexural strength is maximum in the vicinity of the beltline, and gradually declines with increase in the distance from beltline's vicinity toward the upper and lower ends. Therefore, a distribution of strength that corresponds to the distribution of side-collision load can be achieved. Besides, the distribution of strength can be adjusted by the outer reinforcement 24, without providing another reinforcing member, nor increasing the strength of an unnecessary portion to an unnecessary level. Therefore, using a minimum amount of materials and members, the strength can be appropriately reinforced.

[0037] Besides, due to the structure in which the vicinity of the beltline which is a portion where the greatest load acts at the time of a side collision is made higher in strength than other portions and the strength is gradually decreased, it is possible to restrain concentration of load to a portion of the center pillar 4 and therefore restrain the buckling of the portion, and if the center pillar 4 deforms or buckles, the buckling can be caused to occur at an appropriate site. Therefore, reduced likelihood of occurrence of buckling can be achieved more efficiently than in the case where the flexural strength of the entire center pillar 4 is improved. Besides, the behavior of the center pillar 4 at the time of occurrence of deformation and the time of occurrence of buckling can be controlled.

[0038] It is to be noted herein that the protrusion/depression portion of the outer reinforcement 24 may be formed extending in a certain region in the vehicle vertical direction, as in the first embodiment. Concretely, as for the outer reinforcement 24, an upper end portion of the protrusion/depression portion in the upward direction may be to the upper side of the seatbelt anchor 18, or may also be in the vicinity of the seatbelt anchor 18. If the end portion of the protrusion/depression portion in the upward direction is disposed in the upper side of the seatbelt anchor 18, it becomes possible to improve the flexural strength of a region where the input of side-collision load to the center pillar 4 is large. If the end port-ion of the protrusion/depression portion in the upward direction is disposed in the vicinity of the seatbelt anchor 18, the region that forms the protrusions .and .the..depressions- ca be restrained from -becoming excessively large, and the center pillar 4 can be reduced in weight. Besides, in the outer reinforcement 24, a lower end portion of the protrusion/depression portion in the downward direction may be disposed in the lower side of the door hinge 17, or may also be disposed in the vicinity of the door hinge 17. If the end portion of the protrusion/depression portion in the downward direction is disposed below the door hinge 17, it becomes possible to improve the flexural strength of a region where the input of side-collision load to the center pillar 4 is large. If the end portion of the protrusion/depression portion in the downward direction is disposed in the vicinity of the door hinge 17, the region that forms the protrusions and the depressions can be restrained from becoming excessively large, and the center pillar 4 can be reduced in weight. Incidentally, in the case where a plurality of door hinges 17 are disposed, an upper-side door hinge may be used as a reference.

[0039] Although in the foregoing center pillar 4, the protrusion/depression surface made up of the protrusion surface 22a and the reference surfaces 22b is provided on the center pillar inner part 22 in order to attain the foregoing effects to a greater degree, this does not the invention. The center pillar inner part 22 may also have a shape that is not provided with a protrusion or a depression.

[0040] Next, with reference to FIGS. 7 and 8, a second embodiment of the center pillar will be described. FIG. 7 is a front view of a center pillar in accordance with the second embodiment. FIG. 8 is a sectional view of the center pillar shown in FIG. 7. Incidentally, in FIG. 7, illustration of a side member outer panel (center pillar outer part) 121 is omitted. Besides, FIG. 8 is a sectional view of a center pillar 104 that is taken along a plane in the proximity of the beltline. A center pillar 104 shown in FIGS. 7 and 8 has the center pillar outer part 121, a center pillar inner part 122 and an outer reinforcement 124. The center pillar outer part 121 has flange portions 134 at two opposite ends thereof in the vehicle longitudinal direction. The center pillar inner part 122 has flange portions 130 at two opposite ends thereof in the vehicle longitudinal direction. The outer reinforcement 124 has flange portions at two opposite ends thereof in the vehicle longitudinal direction. The center, pillar inner part 122. has substantially the same construction as the center pillar inner part 22, except that the center pillar inner part 122 is not provided with a protrusion/depression shape (that includes protrusion surfaces and reference surfaces) whose shape changes depending on the position in the vehicle vertical direction. Besides, the center pillar outer part 121 and the flange portions 130, 132 and 134 are substantially the same in construction as the center pillar outer part 21, the flange portions 30, 32 and 34, respectively, and therefore detailed descriptions thereof will be omitted.

[0041] The outer reinforcement 124 functions as a reinforcing member that ^■ connects the front-side flange portions and the rear-side flange portions of the pillar main parts. As described above, a front side and a rear side of the outer reinforcement 124 are respectively provided with flange portions 132. The outer reinforcement 124 is provided with a projection portion that is protruded to the outer side, between the flange portion 132 provided on the front side and the flange portion 132 provided on the rear side. Thus, the outer reinforcement 124 is basically formed so that the shape of a cross-section thereof orthogonal to the extending direction of the center pillar 104 is a shape that is protruded to the outer side. Incidentally, the projection portion has a surface whose section is a curved line.

[0042] Next, the projection portion of the outer reinforcement 124 will be described. The cross-sectional shape of the outer reinforcement 124 changes depending on the position in the vehicle vertical direction as shown in FIGS. 2 to 5. Concretely, as shown in FIG. 7, an intermediate portion of the center pillar 104 in the vehicle vertical direction is provided with a protrusion/depression portion constructed of a protrusion surface (protrusion portion) 124a that is more protruded to the outer side than the flange portions 132, and two depression surfaces (depression portions) 124b that are more protruded to the inner side (more depressed from the outer side) than the flange portions 132. Incidentally, the protrusion surface 124a has substantially the same shape as a projection portion formed in a region that is outside the region in which the protrusion/depression portion is formed.

[0043] The protrusion portion .124a is formed in a region that includes a center of the outer reinforcement 124 in the vehicle longitudinal direction. The two depression surfaces 124b are disposed on sides of the protrusion surface 124a that are apart from the center of the outer reinforcement 124 in the vehicle longitudinal direction. That is, two opposite ends of the protrusion portion 124a in the vehicle longitudinal direction are linked to the depression surfaces 124b, respectively. In each of the two depression surfaces 124b, an end portion thereof toward the center of the outer reinforcement 124 in the vehicle longitudinal direction is linked to the protrusion surface 124a, and an end portion thereof remote from the center is linked to an adjacent one of the flange portions 132. Thus, the protrusion/depression portion has an arrangement in which the flange portions 132, the depression surfaces 124b and the protrusion surface 124a are disposed in that order from the two opposite end portions to the center in the vehicle longitudinal direction, and therefore has a protrusion/depression shape that is first protruded to the inner side as the distance from each end portion toward the center increases, and then is protruded to the outer side as the distance from each end portion further increases toward the center.

[0044] It is to be noted herein that in the region where the protrusion surface 124a and the depression surfaces 124b are formed, the distances between the protrusion surface 124a and the depression surfaces 124b (the distances therebetween in the vehicle width direction) and the distances between the depression surfaces 124b and the flange portions 132 (the distances therebetween in the vehicle width direction) gradually increase and then gradually decrease with increase in the distance from the upper end of the region toward the lower end thereof in the vehicle vertical direction. That is, as shown in FIG. 7, the depression surfaces 124b have such a shape as to become gradually further apart from the protrusion surface 124a and then become gradually closer thereto. Incidentally, dotted lines shown in FIG. 7 are imaginary lines that indicate the position of the inner-side end portion of the outer reinforcement 124 in the case where the depression surfaces 124b are not provided. In the outer reinforcement 124, the distances between the protrusion surface 124a and the depression surfaces 124b become maximum in the vicinity of the beltline— In other words, the depths of the depression surfaces 124b become maximum in the vicinity of the beltline. That is, in the vicinity of the beltline, there is a site where the amount of processing of the outer reinforcement 124 becomes maximum and the maximum rigidity is retained.

[0045] In the outer reinforcement 124, since, as a protrusion/depression portion, the depression surfaces 124b that are protruded to the inner side are provided at the two opposite end portions in the vehicle longitudinal direction, the distance between a portion that is furthest to the outer side and a portion that is furthest to the inner side in the vicinity of the beltline (i.e., the protrusion/depression height) can be maximized. By increasing the height between a protrusion and a depression, the flexural strength in a section can be heightened. Concretely, because the height of the wall surface extending in a direction substantially parallel to the vehicle width direction, deformation in the vehicle width direction becomes less likely. This results in less likelihood of deformation when a side-collision load acts. Besides, because the protrusion/depression height becomes maximum at the beltline, and gradually decreases with increase in the distance from the beltline in the vehicle vertical direction, it is possible to make an appropriate distribution of the flexural rigidity. Therefore, the center pillar 104 is able to attain substantially the same effects as the above-described center pillar 4.

[0046] Next, with reference to FIGS. 9 to 11, a third embodiment of the center pillar will be described. FIG. 9 is a front view of a center pillar in accordance with the third embodiment. FIG. 10 is a sectional view of the center pillar shown in FIG. 9. FIG. 11 is an illustrative diagram showing a distribution of force that acts on the center pillar shown in FIG. 10 when the pillar receives side-collision load. Incidentally, in FIG. 9_¾ illustration of a side member outer panel (center pillar outer part) 221 is omitted. Besides, FIG. 10 is a sectional view taken along a plane in the proximity of the beltline of a center pillar 204. The center pillar 204 shown in FIGS. 9 and 10 has the center pillar outer part 221, a center pillar inner part 222 and an outer reinforcement 224. The center pillar outer part 221 has flange portions 234 at two opposite ends thereof in the vehicle longitudinal direction. The center pillar inner part 222 has flange portions 230 at two .opposite- ends thereof in .the. vehicle longitudinal direction The outer reinforcement 224 has flange portions 232 at two opposite ends thereof in the vehicle longitudinal direction. Besides, the center pillar outer part 221, the center pillar inner part 222 and the flange portions 230, 232 and 234 have substantially the same constructions as the center pillar outer part 121, the center pillar inner part 122 and the flange portions 130, 132 and 134, and detailed descriptions thereof will be omitted.

[0047] The outer reinforcement 224 functions as a reinforcing member that connects the front-side flange portions and the rear-side flange portions of the pillar main parts. As described above, a front side and a rear side of the outer reinforcement 224 are respectively provided with the flange portions 232. The outer reinforcement 224 is provided with a projection portion that is protruded to the outer side, between. the flange portion 232 provided on the front side and the flange portion 232 provided on the rear side. Thus, the outer reinforcement 224 is basically formed so that the shape of a cross-section thereof orthogonal to the extending direction of the center pillar 204 is a shape that is protruded to the outer side. Incidentally, the projection portion has a surface whose section is a curved line.

[0048] Next, the projection portion of the outer reinforcement 224 will be described. The cross-sectional shape of the outer reinforcement 224 changes depending on the position in the vehicle vertical direction as shown in FIGS. 9 and 10. Concretely, as shown in FIG. 9, an intermediate portion of the center pillar 204 in the vehicle vertical direction is provided with a protrusion/depression portion constructed of a protrusion surface 224a that is more protruded to the outer side than the flange portions 232 and two depression surfaces 224c that are more protruded to the inner side (more depressed from the outer side) than the flange portions 232. Incidentally, the protrusion surface 224a has substantially the same shape as a projection portion formed in a region that is outside the region in which the protrusion/depression portion is formed. Besides, the protrusion surface 224a of the protrusion/depression portion is provided with a depression surface 224b that is protruded to the inner side (depressed from the outer side), at a center in the vehicle longitudinal direction. Incidentally, the depression surface 224b has such a shape whose section is generally semi-circular. - [0049] The protrusion surface 22ra is formed in a region that includes the center in the vehicle longitudinal direction. Besides, the depression surface (depressed bead portion) 224b is formed in the region that includes the center in the vehicle longitudinal direction, in the protrusion surface 224a. Incidentally, the length of the depression surface 224b in the vehicle longitudinal direction is sufficiently small relative to the length of the protrusion surface 224a in the vehicle longitudinal direction. That is, the depression surface 224b is formed in a portion of a center portion of the protrusion surface 224a. The two depression surfaces 224c are disposed on sides of the protrusion surface 224a that are apart from the center of the outer reinforcement 224 in the vehicle longitudinal direction. That is, two opposite ends of the protrusion portion 224a in the vehicle longitudinal direction are linked to the depression surfaces 224c, respectively. In each of the two depression surfaces 224c, an end portion thereof toward the center of the outer reinforcement 224 in the vehicle longitudinal direction is linked to the protrusion surface 224a, and an end portion thereof remote from the center is linked to an adjacent one of the flange portions 232. Thus, the protrusion/depression portion has an arrangement in which the flange portions 232, the depression surfaces 224c and the protrusion surface 224a whose center portion is provided with the depression surface 224b are disposed in that order from the two opposite end portions to the center in the vehicle longitudinal direction. Therefore, the protrusion/depression portion has. a protrusion/depression shape that is first protruded to the inner side as the distance from each end portion toward the center increases, and then is protruded to the outer side as the distance from each end portion further increases toward the center.

[0050] It is to be noted herein that in the region where the protrusion surface 224a, the depression surface 224b and the depression surfaces 224c are formed, the distance between the protrusion surface 224a and the depression surface 224b (the distance therebetween in the vehicle width direction), the distances between the protrusion surface 224a and the depression surface 224c (the distances therebetween in the vehicle width direction) and the distances between the depression surfaces 224c and the flange , portions 232. (the. distances therebetween in the vehicle width direction) gradually increase and then gradually decrease with increase in the distance from the upper end of the region toward the lower end thereof in the vehicle vertical direction. That is, as shown in FIG. 9, the depression surface 224b has such a shape as to become gradually further apart from the protrusion surface 224a and then become gradually closer thereto. Besides, as shown in FIG. 9, the depression surfaces 224c also have such a shape as to become gradually further apart from the protrusion surface 224a and then become closer thereto. Incidentally, dotted lines shown in FIG. 9 are imaginary lines that indicate the position of the inner-side end portion of the outer reinforcement 224 in the case where the depression surface 224c is not provided. In the outer reinforcement 224, the distance between the protrusion surface 224a and the depression surface 224b and the distances between the protrusion surface 224a and the depression surfaces 224c become maximum in the vicinity of the beltline. In other words, the depths of the depression surface 224b and the depression surfaces 224c become maximum in the vicinity of the beltline. That is, in the vicinity of the beltline, there is a site where the amount of processing of the outer reinforcement 224 becomes maximum and the maximum rigidity is retained.

[0051] In the outer reinforcement 224, since, as a protrusion/depression portion, the depression surfaces 224c that are protruded to the inner side are provided at the two opposite end portions in the vehicle longitudinal direction, the distance between a portion that is furthest to the outer side and a portion that is furthest to the inner side in the vicinity of the beltline (i.e., the protrusion/depression height) can be maximized. Therefore, the outer reinforcement 224 is able to attain substantially the same effects as the outer reinforcement 124.

[0052] Furthermore, in the outer reinforcement 224, since, as a protrusion/depression portion, the depression surface 224b that is protruded to. the inner side is provided in a center portion of the protrusion surface 224a in the vehicle longitudinal direction, the flexural rigidity of the protrusion surface 224a can be improved. Concretely, in the case of an outer reinforcement 250 that has the same shape .as the above-described outer reinforcement 224 except that the depression surface 224b is not provided as shown in FIG. 11 (i.e., in the case of substantially the same shape as that of the outer reinforcement 124 shown in FIGS. 7 and 8), the permissible magnitude of the load is a magnitude that is indicated by a dotted line 260; however, the outer reinforcement 224 is able to allow a load that is larger than the load indicated by the dotted line 260. By providing the depression surface 224b, the flexural strength in a cross-section can be heightened. This results in less likelihood of deformation when a side-collision load acts. Besides, because the depression surface 224b is formed so that the protrusion/depression height becomes maximum at the beltline, and gradually decreases with increase in the distance from the beltline in the vehicle vertical direction (the depression surface 224b eventually disappears), it is possible to make an appropriate distribution of the flexural rigidity. Therefore, the center pillar 204 is able to attain substantially the same effects as the above-described center pillar 104.

[0053] Incidentally, as for the depression surface 224b, the thickness t thereof and the length b thereof in the vehicle longitudinal direction may satisfy b<t/0.04. This will restrain the depression surface 224b from becoming excessively large and therefore restrain the flexural rigidity from declining.

[0054] Next, with reference to FIGS. 12 and 13, a fourth embodiment of the center pillar will be described. FIG. 12 is a front view of a center pillar in accordance , with the fourth embodiment. FIG. 13 is a sectional view of the center pillar shown in FIG. 12. Incidentally, in FIG. 12, illustration of a side member outer panel (center pillar outer part) 321 is omitted. Besides, FIG. 13 is a sectional view of a center pillar 304 taken along a plane in the vicinity of the beltline. The center pillar 304 shown in FIGS. 12 and 13 has the center pillar outer part 321 , a center pillar inner part 322 and an outer reinforcement 324. The center pillar outer part 321 has flange portions 334 at two opposite ends thereof in the vehicle longitudinal direction. The center pillar inner part 322 has flange portions 330 at two opposite ends thereof in the vehicle longitudinal direction. The outer reinforcement 324 has flange portions 332 at two opposite ends thereof in the vehicle longitudinal direction. Besides, the center pillar outer part 321 , ^'.. the center .pillar , inner .part 322 . and- the flange portions 330. 332 -and 334 have substantially the same constructions as the center pillar outer part 121, the center pillar inner part 122 and the flange portions 130, 132 and 134, and detailed descriptions thereof will be omitted.

[0055] The outer reinforcement 324 functions as a reinforcing member that connects the front-side flange portions and the rear-side flange portions of the pillar main parts. As described above, a front side and a rear side of the outer reinforcement 324 are respectively provided with the flange portions 332. The outer reinforcement 324 is provided with a projection portion that is protruded to the outer side, between the flange portion 332 provided on the front side and the flange portion 332 provided on the rear side. Thus, the outer reinforcement 324 is basically formed so that the shape of a cross-section thereof orthogonal to the extending direction of the center pillar 304 is a shape that is protruded to the outer side. Incidentally, the projection portion has a surface whose section is a curved line.

[0056] Next, the projection portion of the outer reinforcement 324 will be described. The cross-sectional shape of the outer reinforcement 324 changes depending on the position in the vehicle vertical direction as shown in FIGS. 12 and 13. Concretely, as shown in FIG. 12, an intermediate portion of the center pillar 304 in the vehicle vertical direction is provided with a protrusion/depression portion constructed of a plurality of protrusion surfaces (three protrusion surfaces in this embodiment) 324a that are more protruded to the outer side than the flange portions 332, and two depression surfaces 324d that are more protruded to the inner side (more depressed from the outer side) than the flange portions 332. Incidentally, in each of the protrusion surfaces 324a, a position that is furthest to the outer side is defined as an apex 324b. Besides, the protrusion surfaces 324a are adjacent to each other, and each protrusion surface 324a and another protrusion surface 324a adjacent thereto are linked by a linking portion 324c. Incidentally, the protrusion/depression portion can be constructed of a plurality of bead portions that have a constant curvature.

[0057] The three protrusion surfaces 324a are disposed in a region that includes a center of. the outer reinforcement 324 in the vehicle longitudinal direction, and are adjacently juxtaposed in the vehicle longitudinal direction. Besides, as described above, each protrusion surface 324a is linked to a protrusion surface 324a adjacent thereof by an adjacent one of the adjacent linking portions 324c. Besides, each of the two end protrusion surfaces 324a disposed at opposite side ends in the vehicle longitudinal direction is linked, at a side end portion thereof that is remote from the center of the outer reinforcement 324, to an adjacent one of the two depression surfaces 324d. Each of the two depression surfaces 324d is disposed at a side of the adjacent protrusion surface 324a which is remote from the center of the outer reinforcement 324 in the vehicle longitudinal direction. That is, in each of the two depression surfaces 324d, an end portion thereof that is toward or close to the center of the outer reinforcement 324 in the vehicle longitudinal direction is linked to the adjacent protrusion surface 324a, and an end portion thereof that is remote from the center is linked to the adjacent one of the two flange portions 332. Thus, the protrusion/depression portion has an arrangement in which the flange portions 332, the depression surfaces 324d and the plurality of protrusion surfaces 324a are disposed in that order from the two opposite end portions to the center in the vehicle longitudinal direction, and therefore has a protrusion/depression shape that is first protruded to the inner side as the distance from each end portion toward the center increases, and then is protruded to the outer side as the distance from each end portion further increases toward the center. Besides, since the plurality of protrusion surfaces 324a are disposed in the vehicle longitudinal direction, the position of a point on the protrusion surfaces 324a in the vehicle width direction shifts to the inner side after the point moves past the apex of a protrusion surface 324a in the vehicle longitudinal direction, and then shifts to the outer side as the point moves along the next protrusion surface 324a after passing the adjacent linking portion 324c in the vehicle longitudinal direction.

[0058] It is to be noted herein that in the region where the protrusion surfaces 324a and the depression surfaces 224d are formed, the distances between the protrusion surfaces 324a (the apexes 324b thereof) and the depression surfaces 224d (the distances therebetween in .the vehicle width direction) .and..the distances between the apexes 324b of the protrusion surfaces 324a and the linking portions 324c (the distances therebetween in the vehicle width direction) gradually increase and then gradually decrease with increase in the distance from the upper end of the region toward the lower end thereof in the vehicle vertical direction. That is, as shown in FIG. 12, the depression surfaces 324d have such a shape as to become gradually further apart from the protrusion surfaces 324a and then become gradually closer thereto. Besides, as shown in FIG. 12, the protrusion surfaces 324a also have such a shape that the apexes 324b of the protrusion surfaces 324a become gradually further apart from the linking portions 324c and then become gradually closer thereto. Incidentally, dotted lines shown in FIG. 12 are imaginary lines that indicate the position of the inner-side end portion of the outer reinforcement 324 in the case where the depression surfaces 324d are not provided. In the outer reinforcement 324, the distances between the protrusion surfaces 324a and the depression surfaces 324d and the distances between the apexes 324b of the protrusion surfaces 324a and the linking portions 324c become maximum in the vicinity of the beltline. In other words, the depths of the depression surfaces 324d become maximum and the height of each protrusion surface 324a becomes maximum in the vicinity of the beltline. That is, in the vicinity of the beltline, there is a site where the amount of processing of the outer reinforcement 324 becomes maximum and the maximum rigidity is retained.

[0059] In the outer reinforcement 324, since, as a protrusion/depression portion, the depression surfaces 324d that are protruded to the inner side are provided at the two opposite end portions in the vehicle longitudinal direction, the distance between a portion that is furthest to the outer side and a portion that is furthest to the inner side in the vicinity of the beltline (i.e., the protrusion/depression height) can be maximized. Therefore, the outer reinforcement 324 is able to attain substantially the same effects as the outer reinforcement 124.

[0060] Furthermore, in the outer reinforcement 324, since, as a protrusion/depression portion, the plurality of protrusion surfaces 324a are provided, the size of an arc of each of the protrusion surfaces can be made relatively small, and the flexural rigidity of the protrusion, surfaces.324a can be further, improved This results in less likelihood of deformation when a side-collision load acts. Besides, because each protrusion surface 324a is formed so that the protrusion/depression height becomes maximum at the beltline, and gradually decreases with increase in the distance from the beltline in the vehicle vertical direction, it is possible to make an appropriate distribution of the flexural rigidity. Therefore, the center pillar 304 is able to attain substantially the same effects as the above-described center pillar 104.

[0061] Next, with reference to FIGS. 14 and 15, a fifth embodiment of the center pihar will be described. FIG. 14 is a front view of a center pillar in accordance with the fifth embodiment. FIG. 15 is a sectional view of the center pillar shown in FIG. 14. Incidentally, in FIG 14, illustration of a side member outer panel (center pillar outer part) 421 is omitted. Besides, FIG. 15 is a sectional view of a center pillar 404 taken along a plane in the vicinity of the beltline The center pillar 404 shown in FIGS. 14 and 15 has the center pillar outer part 421 , a center pillar inner part 422 and an outer reinforcement 424. The center pillar outer part 421 has flange portions 434 at two opposite ends thereof in the vehicle longitudinal direction. The center pillar inner part 422 has flange portions 430 at two opposite ends thereof in the vehicle longitudinal direction. The outer reinforcement 424 has flange portions 432 at two opposite ends thereof in the vehicle longitudinal direction. Besides, the center pillar inner part 422 has substantially the same construction as the center pillar inner part 22, except that the center pillar inner part 422 is not provided with a protrusion/depression shape (including a protrusion surface and a reference surface) that changes in its shape depending on the position in the vehicle vertical direction. Besides, the center pillar outer part 421 and the flange portions 430, 432 and 434 have substantially the same constructions as the center pillar outer part 21 and the flange portions 30, 32 and 34, and detailed descriptions thereof will be omitted.

[0062] The outer reinforcement 424 functions as a reinforcing member that connects the front-side flange portions and the rear-side flange portions of the pillar main parts. As described above, a front side and a rear side of the outer reinforcement 424 are _L_ respectively provided with.. the. flange portions .432.... The. outer reinforcement 424 is provided, with a projection portion that is protruded to the outer side, between the flange portion 432 provided on the front side and the flange portion 432 provided on the rear side. Thus, the outer reinforcement 424 is basically formed so that the shape of a cross-section thereof orthogonal to the extending direction of the center pillar 404 is a shape that is protruded to the outer side.

[0063] Next, the projection portion of the outer reinforcement 424 will be described. The cross-sectional shape of the outer reinforcement 424 changes depending on the position in the vehicle vertical direction as shown in FIGS. 14 and 15. Concretely, as shown in FIG. 14, an intermediate portion of the center pillar 404 in the vehicle vertical direction is provided with a protrusion/depression portion in which protrusion surfaces 424a that are protruded to the outer side and depression surfaces 424b that are protruded to the inner side (depressed from the outer side) are alternately arranged. Incidentally, the protrusion/depression portion can be constructed of a plurality of bead portions that have a constant curvature.

[0064] At least one end portion of each of the protrusion surfaces 424a in the vehicle longitudinal direction is linked to an adjacent one of the depression surfaces 424b. Besides, end portions of the depression surfaces 424b in the vehicle longitudinal direction are linked to the protrusion portions 424a. Incidentally, two opposite end portions of the shape of repetitions of the protrusion surfaces 424a and the depression surfaces 424b in the vehicle longitudinal direction are both provided with protrusion surfaces 424a, and are linked to the flange portions 432. Thus, the protrusion/depression portion has an arrangement in which, from each of the two opposite ends toward the center in the vehicle longitudinal direction, the flange portion 432, the protrusion surface 424a and a depression surface 424b are disposed in that order followed by one or more repetition units of a protrusion surface 424a and a depression surface 424b. Therefore, the protrusion/depression portion has a protrusion/depression shape in which protrusion to the outer side appears as the distance from each end portion toward the center in the vehicle longitudinal direction increases, and in which, following the protrusion, a shape that is. protruded. to the inner side in. a depression. surface.424b and-that is protruded to the outer side in a protrusion surface 424a is repeated once or more.

[0065] It is to be noted herein that in the region where the protrusion surfaces 424a and the depression surfaces 424b are formed, the distances between the protrusion surfaces 424a and the depression surfaces 424b (the distances therebetween in the vehicle width direction) gradually increase and then gradually decrease with increase in the distance from the upper end of the region toward the lower end thereof in the vehicle vertical direction. That is, as shown in FIG. 14, the outer reinforcement 424 has such a shape that the outermost point (point that is furthest to the outer side) on each protrusion surface 424a and the innermost point (point that is furthest to the inner side on each depression surface 424b become gradually further apart from each other and then become gradually closer to each other. In the outer reinforcement 424, the distances between the protrusion surfaces 424a and the depression surfaces 424b become maximum in the vicinity of' the beltline. In other words, the heights or depths of the protrusions and depressions become maximum in the vicinity of the beltline. That is, in the vicinity of the beltline, there is a site , where the amount of processing of the outer reinforcement 424 becomes maximum and the maximum rigidity is retained.

[0066] In the outer reinforcement 424, since, as a protrusion/depression portion, a protrusion/depression shape in which protrusion surfaces and depression surfaces are alternately disposed is provided, the size of an arc of each one of the protrusion surfaces and the depression surfaces can be lessened, and the flexural rigidity of the protrusion surfaces 424a can be improved. Besides, the surfaces that connect the protrusion , surfaces and the depression surfaces are surfaces that extend in the vehicle width direction, so that the flexural rigidity of the outer reinforcement 424 can be further improved. This results in less likelihood of deformation of the outer reinforcement 424 when a side-collision load acts. Besides, because the protrusion/depression height in the outer reinforcement 424 becomes maximum at the beltline, and gradually decreases with increase in the distance from the beltline in the vehicle vertical direction, it is possible to make an appropriate distribution of the flexural rigidity. Therefore, the center pillar 404 ...is able. to. attain. substantially the. same effects, as the abave-described center pillar 4. [0067] Incidentally, the shape of the center pillar is not limited by the foregoing embodiments. The center pillar may have a shape that is obtained by combining constructions of any two or more of the foregoing embodiments. The outer reinforcement can attain the foregoing effects if the outer reinforcement is provided with a protrusion/depression portion whose shape is gradually changed in the vehicle vertical direction so that the heights or depths of the protrusions and the depressions in the vehicle width direction become maximum in the vicinity of the beltline. Incidentally, the outer reinforcement may have a shape in which the center of the outer reinforcement in the vehicle longitudinal direction is to the outer side of the flange portions. If the center of the outer reinforcement in the vehicle longitudinal direction is placed to the outer side of the flange portions, a portion of the outer reinforcement in which the side-collision load becomes large is placed further to the outer side, and therefore the flexural rigidity thereof can be made greater. This makes the center pillar less apt to bend and less apt to buckle. Besides, the shapes of the depression surfaces and the protrusion surfaces are not limited to a shape whose section is a straight line or a shape whose section is a curved line, but may also be a shape obtained by combining a curved line and a straight line.

[0068] As described above, the vehicle center pillar of the invention is useful for improving the strength of withstanding the side-collision load, and is particularly useful for improving the strength of withstanding the side-collision load while reducing the weight.

Claims

CLAIMS:

1. A vehicle structural part including:

an outer member that extends in a vertical direction of a vehicle, that has outer flange portions at a front side and a rear side of the outer member in a longitudinal direction of the vehicle, and that has a portion between the outer flange portion at the front side and the outer flange portion at the rear side protruded from the outer flange portions to an outer side in a vehicle width direction;

an inner member that extends in the vertical direction, that has, at the front side and the rear side of the inner member in the longitudinal direction, inner flange portions that engage with the outer flange portions of the outer member respectively, and that is disposed to an inner side of the outer member in the vehicle width direction; and

a reinforcing member that is disposed between the outer member and the inner member, that has center flange portions at the front side and the rear side of the reinforcing member in the longitudinal direction of the vehicle, and that has a central portion that is located between the two center flange portions and located on the outer side of the center flange portions in the vehicle width direction,

the vehicle structural part being characterized in that:

the reinforcing member has a projection portion that is formed such that, from an upper side toward a lower side in the vertical direction, a distance in the vehicle width direction between an end portion in the outer side and an end portion in the inner side of the projection portion increases, becomes maximum near a beltline, and then decreases.

2. The vehicle structural part according to claim 1, wherein an upper-side end portion of the projection portion in the vertical direction is disposed in the upper side of an upper-side end portion of a seatbelt anchor of the vehicle.

3. The vehicle structural part according to claim 1 , wherein an upper-side end portion of the projection portion in the vertical direction is disposed in proximity of an upper-side end portion of a seatbelt anchor.

4. The vehicle structural part according to any one of claims 1 to 3, wherein a lower-side end portion of the projection portion in the vertical direction is disposed in the lower side of an upper end of a door hinge of the vehicle.

5. The vehicle structural part according to any one of claims 1 to 3, wherein a lower-side end portion of the projection portion in the vertical direction is in proximity of an upper end of a door hinge of the vehicle.

6. The vehicle structural part according to any one of claims 1 to 5, wherein the projection portion includes a protrusion portion that is provided in proximity of a center of the reinforcing member in the longitudinal direction, and that is protruded to the outer side relative to the vehicle.

7. The vehicle structural part according to claim 6, wherein:

the projection portion includes a plurality of the protrusion portions; and

the protrusion portions are linked to each other in the longitudinal direction.

8. The vehicle structural part according to any one of claims 1 to 5, wherein the projection portion includes a depression portion that is provided in proximity of a center of the reinforcing member in the longitudinal direction, and that is protruded to the inner side relative to the vehicle.

9. The vehicle structural part according to any one of claims 1 to 8, wherein the projection portion includes an end-side depression portion that is provided in proximity of at least one of end portions of the reinforcing member in the longitudinal direction, and that is protruded to the inner side relative to the vehicle. .

10.. The vehicle- structural part according to any one of claims 1 to 9, wherein the center flange is engaged between the outer flange and the inner flange.

11. A vehicle structural part including:

an outer member extending in a vertical direction of a vehicle;

an inner member extending in the vertical direction of the vehicle; and

a reinforcing member held between the outer member and the inner member, the vehicle structural part being characterized in that:

a height of a protrusion portion provided in the reinforcing member or a depth of a depression portion provided in the reinforcing member is maximum in proximity of a beltline, and the height of the protrusion portion or the depth of the depression portion decreases from the beltline toward an upper side or a lower side.

12. A vehicle structural part including:

an outer member extending in a vertical direction of a vehicle;

an inner member extending in the vertical direction of the vehicle; and '

a reinforcing' member held between the outer member and the inner member, the vehicle structural part being characterized in that:

an amount of processing of a protrusion portion provided in the reinforcing member _, or a depression portion provided in the reinforcing member is maximum in proximity of a beltline, and the amount of processing of the depression portion or the protrusion portion decreases from the beltline toward an upper side or a lower side.

13. The vehicle structural part according to any one of claims 1 to 12, which is provided in a center pillar.