Side member and vehicle body equipped with same

Abstract

The first member 100 of the side member 2 includes a pair of first end walls 103, 104, a first side wall 105, and a protruding strip 106 provided on the first side wall 105. A pair of branched portions 105b, 105c of the first side wall 105 have an inclined portion 105e that extends from the tip 20 of the side member 2 toward the rear so as to approach an apex 123 of the protruding strip 106. The first side wall 105 is flush with the apex 123 at a midpoint of the side member 2 in the front-rear direction X. A first bead 107 extending in the front-rear direction X is formed on the first side wall 105 at a flat portion 105a that is flush with the apex 123.

Description

[Technical field]

[0001] The present invention relates to a side member and a vehicle body equipped with the same. [Background technology]

[0002] A front side member is provided as a side member provided on the body of a vehicle such as a passenger car (see, for example, Patent Documents 1 to 3). The side frame as a side member described in Patent Document 1 extends in the front-rear direction of the vehicle. The side frame is a member with a closed cross-sectional structure composed of an inner member located on the inside in the vehicle width direction and an outer member located on the outside in the vehicle width direction. The inner member of the side frame has band-shaped upper and lower surface portions extending in the front-rear direction facing each other vertically, and inner side surfaces connected to both side edges on the inside in the vehicle width direction of the upper and lower surface portions. An inner band-shaped protrusion having a U-shaped cross section is formed on the front end side of the inner side surface portion, extending in the front-rear direction at the middle in the vertical width direction. The inner band-shaped protrusion is formed so that the protrusion amount in the vehicle width direction gradually decreases from the front end to the rear end. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2010-70133 A [Patent Document 2] JP 2013-14289 A [Patent Document 3] JP 2012-1023 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, as is clear from the description of Figure 3 in Cited Document 1, the rear end of the inner band-shaped protrusion is connected obliquely to the inner surface of the inner member at the connection portion with the inner surface. Therefore, when a moving vehicle collides with a wall or the like and the side frame is axially crushed (compressed by buckling) to absorb impact energy, a bending force acts on the side frame at the rear end of the inner band-shaped protrusion. When such a bending force acts, the axial crush of the side frame is not promoted and the amount of plastic deformation is reduced, which reduces the efficiency of absorbing impact energy by the plastic deformation of the side frame.

[0005] In addition, other vehicle body components, such as suspension towers, are fixed to the inner member by welding or adhesive. For this reason, the inner member needs to have a sufficient area for mounting the other components. However, Patent Document 1 does not disclose any idea or configuration for ensuring a large area for mounting the other components to the inner member.

[0006] In view of the above background, one object of the present disclosure is to provide a side member that can increase the efficiency of absorbing impact energy and ensure a larger area on which other vehicle body components can be attached, and a vehicle body equipped with the same. [Means for solving the problem]

[0007] The present disclosure relates to the following side member and vehicle body.

[0008] (1) A side member extending in the fore-and-aft direction of a vehicle, A first member having a hat-shaped cross section perpendicular to the front-rear direction; A second member joined to the first member and cooperating with the first member to form a closed cross-sectional shape; Equipped with the first member includes a pair of first end walls rising from a joint with the second member, a first side wall disposed between the pair of first end walls, and a convex strip provided on the first side wall, extending in the front-rear direction from a tip of the first member in the front-rear direction and having a convex shape in a direction away from the second member, the first side wall has a portion extending in the front-rear direction so as to approach the apex of the protrusion as it moves away from the tip of the first member, and is flush with the apex at a midpoint in the front-rear direction; The first side wall has a bead formed at a location flush with the top portion, the bead extending in the front-rear direction.

[0009] (2) The side member described in (1) above, wherein the tip of the bead is positioned on the apex at a location where the first side wall and the apex are flush with each other in the fore-and-aft direction, or at a location moving from that location toward the tip of the first member.

[0010] (3) The second member includes a pair of second end walls rising from a joint with the first member and a second side wall disposed between the pair of second end walls, The side member described in (1) or (2), wherein the second member has a recess formed on the second side wall, extending in the fore-and-aft direction from a tip of the second member in the fore-and-aft direction and recessed toward the first member.

[0011] (4) The side member according to (3), wherein the recess includes a portion that becomes shallower as it moves away from the tip of the second member in the front-rear direction.

[0012] (5) A side member as described in any one of (1) to (4), wherein at the tip of the first member and the tip of the second member in the fore-and-aft direction, the height of the first member from the joint is greater than the height of the second member from the joint.

[0013] (6) The side member according to any one of (1) to (5), wherein a second bead extending in a direction intersecting the front-rear direction is provided on each of the first member and the second member.

[0014] (7) The first member includes a pair of first flanges extending from the pair of first end walls, the second member includes a pair of second flanges joined to the pair of first flanges and constituting the joint portion together with the pair of first flanges, The side member according to (6), wherein the second bead is formed on the first flange and the second flange in a region where the protruding strip is arranged in the front-rear direction.

[0015] (8) A side member according to any one of (1) to (7), a vehicle body member joined to the first member of the side member. Effect of the Invention

[0016] According to the present disclosure, the impact energy absorption efficiency of the side member can be increased, and a larger area can be secured to which other vehicle body members can be attached. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 is a perspective view showing a main portion of a side member provided on a vehicle body according to an embodiment of the present disclosure. [Diagram 2] FIG. 2 is a perspective view showing a state in which the side member of FIG. 1 is turned over by 180 degrees. [Diagram 3] FIG. 3 is a plan view of the first member of the side member. [Figure 4] FIG. 4 is a plan view of the second member of the side member. [Diagram 5] FIG. 5 is a cross-sectional view taken along line VV in FIG. 3, and the portion behind the cross section is not shown. [Figure 6]FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. 3, and the portion behind the cross section is omitted. [Figure 7] FIG. 7 is a side view of the side member as viewed along the height direction Z. FIG. [Figure 8] FIG. 8 is a perspective view of a comparative example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] (Overview of the embodiment) FIG. 1 is a perspective view showing a main part of a side member 2 provided in a vehicle body 1 according to an embodiment of the present disclosure. FIG. 2 is a perspective view showing a state in which the side member 2 of FIG. 1 is turned over 180 degrees. FIG. 3 is a plan view of a first member 100 of the side member 2. FIG. 4 is a plan view of a second member 200 of the side member 2. FIG. 5 is a cross-sectional view taken along line VV in FIG. 3, with the illustration of the part behind the cross section omitted. FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. 3, with the illustration of the part behind the cross section omitted. FIG. 7 is a side view of the side member 2 as viewed along the height direction Z.

[0019] As shown in Figures 1 to 7, the vehicle body 1 of this embodiment is the body of an automobile. The vehicle body 1 is, for example, a passenger car. Examples of the passenger car include a sedan type passenger car, a coupe type passenger car, a hatchback type passenger car, a minivan type passenger car, and an SUV (Sport Utility Vehicle) type passenger car.

[0020] The vehicle body 1 includes a side member 2. The side member 2 is one of the frame members for supporting a prime mover such as an engine or an electric motor of an automobile, and an auxiliary device such as a battery, and is an impact absorbing member. The impact absorbing member is a member that absorbs an impact when the automobile collides with an object. The side member 2 is an axially crushable part serving as an impact absorbing member. The axially crushable part absorbs an impact by collapsing while being compressed (axially crushed) in the axial direction of the axially crushable part. The side member 2 has a portion that extends in the fore-and-aft direction X of the vehicle body 1 (vehicle). In this embodiment, the vehicle length direction, vehicle width direction, and vehicle height direction of the vehicle body 1 are referred to as the fore-and-aft direction X, the width direction Y, and the height direction Z, respectively.

[0021] The side member 2 includes a first member 100 having a hat-shaped cross section perpendicular to the front-rear direction X, and a second member 200 joined to the first member 100 and forming a closed cross-sectional shape in cooperation with the first member 100. The closed cross-sectional shape refers to an endless shape (a shape without interruptions) when tracing the side member 2 in the circumferential direction of the side member 2 in a cross section perpendicular to the front-rear direction X.

[0022] The first member 100 has a pair of first flanges 101, 102 joined to the second member 200, a pair of first end walls 103, 104 rising from the pair of first flanges 101, 102, a first side wall 105 arranged between the pair of first end walls 103, 104, and a convex rib 106 provided on the first side wall 105, extending in the fore-and-aft direction X from the tip of the first member 100 in the fore-and-aft direction X and having a convex shape in the direction away from the second member 200.

[0023] The first side wall 105 has a portion that approaches the apex 123 of the protruding strip 106 as it moves away from the tip of the first member 100 in the front-rear direction X, and is flush with the apex 123 at a midpoint of the first member 100 in the front-rear direction X. The midpoint of the first member 100 in the front-rear direction X refers to a position between the front end and the rear end of the first member 100 in the front-rear direction X, and can also be called an intermediate position. A first bead 107 extending in the front-rear direction X is formed on the first side wall 105 at a location flush with the apex 123.

[0024] With the above-mentioned configuration, it is possible to increase the efficiency of absorbing impact energy in the side member 2, and also to ensure a larger area to which other vehicle body members (suspension towers 3) can be attached.

[0025] The above is an outline of this embodiment. Next, a more specific configuration of the vehicle body 1 will be described.

[0026] (Details of the embodiment) In this embodiment, the vehicle body 1 includes a side member 2 and a suspension tower 3 joined to a first member 100 of the side member 2 as a vehicle body member.

[0027] In this embodiment, the side member 2 is a front side member, and is installed in front of the passenger compartment (not shown). The side member 2 is provided to absorb impact energy due to an impact load acting on the side member 2 in the front-rear direction X when the vehicle collides with a wall or the like while moving forward. A pair of side members 2 are installed on the left and right sides of the vehicle body 1, but since the pair of side members 2 have a symmetrical shape in the width direction Y, the configuration of one of the side members 2 will be described in this disclosure.

[0028] The side member 2 extends along the front-rear direction X. As described above, the side member 2 is an impact absorbing member, and also a suspension tower support member to which the suspension tower 3 is attached. The tip 20 of the side member 2 is the end of the side member 2 on the front side of the vehicle. A bumper beam is connected to the tip 20 of the side member 2 via a crash box (not shown) or the like. The side member 2 is formed of a steel plate, an aluminum alloy plate, a carbon fiber reinforced plastic, a composite material thereof, or the like.

[0029] When the side member 2 is made of steel plate, the tensile strength of the side member 2 is, for example, 590 MPa to 1470 MPa. In this case, the lower limit of the tensile strength may be 980 MPa or 1180 MPa. When the side member 2 is made of steel plate, the plate thickness of the side member 2 is, for example, about 1.0 mm to 2.0 mm. The side member 2 is a structural member that supports the vehicle's own weight, and has a plate thickness greater than exterior members such as panels.

[0030] The portion of the side member 2 shown in the drawing is a part of the side member 2, and has a length in the front-rear direction X of about 400 mm. The specific shape of the portion of the side member 2 rearward of the rear end 23 of the portion shown in the drawing is not important.

[0031] As described above, the side member 2 has the first member 100 and the second member 200.

[0032] In this embodiment, the first member 100 and the second member 200 are aligned in the width direction Y, with the first member 100 disposed on the vehicle inner side (center side) in the width direction Y, and the second member 200 disposed on the vehicle outer side in the width direction Y. The tip of the first member 100 and the tip of the second member 200 are both the tip 20 of the side member 2. In this embodiment, the first member 100 and the second member 200 have shapes symmetrical in the height direction Z.

[0033] (First member) As described above, the first member 100 has a pair of first flanges 101, 102, a pair of first end walls 103, 104, a first side wall 105, a ridge 106, and a first bead 107. It is preferable that the first member 100 further includes second beads 111-116 as in this embodiment.

[0034] In this embodiment, the pair of first flanges 101, 102 are disposed at the upper end and the lower end of the first member 100. Each of the first flanges 101, 102 extends from a pair of first end walls 103, 104 along the height direction Z, and is a portion of the side member 2 that protrudes upward and downward. In the region where each of the first flanges 101, 102 is aligned with the protruding strip 106 in the height direction Z, the length in the height direction Z of the first flanges 101, 102 changes, and the tip 20 side of the side member 2 is relatively short and the rear side of the side member 2 is relatively long. A pair of second flanges 201, 202 of the second member 200, which will be described later, are formed in the same shape. With this configuration, when an impact load during a frontal collision of the vehicle acts on the side member 2, the tip 20 side portion of the side member 2 including the protruding strip 106 can be preferentially axially crushed. A pair of first end walls 103, 104 are connected to the pair of first flanges 101, 102.

[0035] The pair of first end walls 103, 104 extend inward in the width direction Y from the corresponding first flanges 101, 102. Each of the first end walls 103, 104 may be parallel to the width direction Y, or, as in this embodiment, may be inclined with respect to the width direction Y such that the distance between the pair of first end walls 103, 104 becomes narrower as the distance increases from the corresponding first flanges 101, 102. A first side wall 105 is connected to the pair of first end walls 103, 104.

[0036] The first side wall 105 is a portion facing inward in the width direction Y. A protruding rib 106 protrudes inward in the width direction Y from a middle portion of the first side wall 105 in the height direction Z.

[0037] The convex strip 106 is provided as a portion that increases the number of ridges in the first member 100. The convex strip 106 is formed from the tip 20 of the side member 2 to the middle portion of the side member 2 in the front-rear direction X. The convex strip 106 is formed, for example, by bending a blank that is the material of the first member 100, and has a different shape from a first bead 107 that is formed by recessing a part of the material of the first member 100. The height Wif-Wifs of the convex strip 106 at the tip 20 of the side member 2 is larger than the depth of the first bead 107, and is set to, for example, 20 mm or more (approximately 30 mm).

[0038] The ridge 106 has a pair of ridge end walls 121, 122 connected to the first side wall 105 and an apex 123 connected to the ridge end walls 121, 122.

[0039] The pair of ridge end walls 121, 122 extend inward in the width direction Y from the first side wall 105. Each ridge end wall 121, 122 may be parallel to the width direction Y, or, as in this embodiment, may be inclined with respect to the width direction Y such that the distance between the pair of ridge end walls 121, 122 narrows with increasing distance from the first side wall 105. An apex 123 is connected to the pair of ridge end walls 121, 122.

[0040] The apex 123 is a tip portion of the first member 100 in the width direction Y, and is a portion perpendicular to the width direction Y. The apex 123 extends straight along the front-rear direction X in this embodiment.

[0041] To explain the first side wall 105 in more detail in relation to the convex rib 106, the first side wall 105 has a flat portion 105a arranged rearward of the convex rib 106, and a pair of branch portions 105b, 105c branching forward from the flat portion 105a and arranged on both the upper and lower sides of the convex rib 106.

[0042] In this embodiment, the flat portion 105a is a flat portion perpendicular to the width direction Y. The width direction Y is, for example, a direction perpendicular to both the side walls 105, 205 of the first and second members 100, 200. In the front-rear direction X, the position of the tip 105a1 of the flat portion 105a coincides with the position of the rear end 106a of the protruding strip 106. The outer surface of the flat portion 105a and the outer surface of the apex 123 of the protruding strip 106 (the surface facing the inside in the width direction Y) are flush with each other and form a continuous flat surface. The flat portion 105a is a portion where the pair of branch portions 105b, 105c and the apex 123 of the protruding strip 106 join together, and is a portion where the three outer surfaces of the branch portions 105b, 105c and the protruding strip 106 are integrated into one. The suspension tower 3 is fixed to the outer surface of the flat portion 105a and the outer surface of the top portion 123 by welding and / or adhesive.

[0043] The pair of branch portions 105b, 105c extend from a tip 105a1 of the flat portion 105a to a tip 20 of the side member 2. The length (width) of the ridge 106 in the height direction Z is greater than the length (width) of each of the branch portions 105b, 105c in the height direction Z. This ensures a sufficient length of the ridge 106 in the height direction Z. The branch portion 105b is connected to the ridge end wall 121, and the branch portion 105c is connected to the ridge end wall 122.

[0044] Each of the branches 105b, 105c has a tip portion 105d and an inclined portion 105e disposed rearward of the tip portion 105d.

[0045] The tip portion 105d extends straight rearward from the tip 20 of the side member 2 in the front-rear direction X. The inclined portion 105e is disposed rearward of the rear end 105d1 of the tip portion 105d, and is inclined toward the apex 123 of the protruding strip 106 as it advances rearward. In this embodiment, the tip portion 105d has a constant length (width) in the height direction Z. On the other hand, the inclined portion 105e becomes narrower as it advances rearward. The rear end 105e1 of the inclined portion 105e is aligned with the rear end 106a of the protruding strip 106 in the front-rear direction X.

[0046] In the front-rear direction X, the length of the inclined portion 105e is longer than the length of the tip portion 105d. This allows the inclined portion 105e to be longer in the front-rear direction X, and reduces the shape change of the inclined portion 105e when the inclined portion 105e advances along the front-rear direction X. Therefore, when an impact force along the front-rear direction X acts on the side member 2, the inclined portion 105e can be prevented from being bent. Each inclined portion 105e is formed in a shape that continuously advances toward the apex 123 of the protruding portion 106 as it advances rearward. The height (length in the width direction Y) of the protruding end walls 121, 122 adjacent to the inclined portion 105e becomes shorter toward the rear end side of each inclined portion 105e. That is, the difference in height between the first side wall 105 and the protruding portion 106 is largest at the tip 20 of the side member 2, and gradually becomes smaller as it advances rearward from the tip 20.

[0047] With the above configuration, the length (height from the first flanges 101, 102) of the pair of first end walls 103, 104 in the width direction Y is constant where the tip portion 105d is located, and becomes longer toward the rear where the inclined portion 105e is located.

[0048] Next, the configuration of the first bead 107 will be described.

[0049] The first bead 107 is provided on the rear side of the protruding strip 106 in order to increase strength against an impact load along the fore-and-aft direction X. The first bead 107 functions to preferentially axially crush a portion of the side member 2 on the tip end 20 side (a portion where the protruding strip 106 is formed) when the side member 2 is axially crushed by an impact load along the fore-and-aft direction X.

[0050] The first bead 107 is formed at least on the flat portion 105a of the first side wall 105. The first bead 107 is a recessed portion extending along the front-rear direction X, and is formed in a shape recessed from the flat portion 105a toward the second member 200 side. The first bead 107 may be formed in a shape protruding from the flat portion 105a to the opposite side to the second member 200. In the front-rear direction X, the first bead 107 may be formed in the entire area of ​​the flat portion 105a, or may be formed only in a part of the flat portion 105a.

[0051] The depth of the first bead 107 is about several mm to 15 mm, for example, 10 mm. By making the depth of the first bead 107 a certain level or more, the stiffening effect of the first bead 107 can be more reliably exhibited. The width (length in the height direction Z) of the first bead 107 is preferably 25% to 95% of the width (length in the height direction Z) of the convex strip 106. By making the width of the first bead 107 equal to or greater than the above-mentioned lower limit, the stiffening effect of the first bead 107 can be more reliably exhibited. Furthermore, by making the width of the first bead 107 equal to or less than the above-mentioned upper limit, the first bead 107 can be extended to the convex strip 106, and the stiffening effect of the first bead 107 for the convex strip 106 can be more reliably exhibited. Furthermore, by making the width of the first bead 107 equal to or less than the above-mentioned upper limit, a larger area of ​​the flat portion 105a of the first side wall 105 can be secured, and a larger area in which the suspension tower 3 can be joined can be secured in terms of design.

[0052] The tip of the first bead 107 is formed in a semicircular shape when viewed from the width direction Y, and the first bead 107 extends straight from this tip to the rear in the front-rear direction X. The first bead 107 preferably extends over both the flat portion 105a of the first side wall 105 and the apex 123 of the protruding strip 106. In this embodiment, the tip 107a of the first bead 107 is disposed on the apex 123 at a location from a location where the first side wall 105 and the apex 123 are flush with each other in the front-rear direction X (the tip 105a1 of the flat portion 105a) toward the tip 20 of the side member 2. The tip 107a of the first bead 107 is preferably located about 10 mm to 150 mm forward from the tip 105a1 of the flat portion 105a, and more preferably about 75 mm to 150 mm forward. With this arrangement, when the side member 2 is axially crushed by an impact load along the front-rear direction X, the branched portions 105b, 105c and the protruding strip 106 are gathered together, so that buckling is less likely to occur at the flat portion 105a, which is shaped to be prone to stress concentration. As a result, in the side member 2, a portion forward of the portion where the first bead 107 is provided is preferentially crushed, so that the portion on the tip 20 side of the side member 2 is easily crushed. Therefore, the efficiency of absorbing impact energy by the side member 2 can be increased. As a method of identifying the rear end 106a of the protruding strip 106, a flat portion at a position a predetermined distance rearward from the tip 107a of the first bead 107 may be regarded as the rear end 106a.

[0053] It is preferable that the tip 107a of the first bead 107 is 150 mm or more rearward from the tip 20 of the side member 2. If the first bead 107 is too close to the tip 20 of the side member 2, when an impact load in the front-rear direction X acts on the side member 2, the behavior of the axial crushing of the first member 100 and the second member 200 at the tip 20 of the side member 2 is likely to differ between the first member 100 and the second member 200. Therefore, in order to axially crush the first member 100 and the second member 200 in a well-balanced manner at the tip 20 of the side member 2, it is preferable that the distance from the tip 20 of the side member 2 to the first bead 107 be the above-mentioned value or more.

[0054] The above-mentioned portions of the first member 100 are connected via a plurality of ridges 131-138.

[0055] Specifically, as shown in FIG. 5, each of the first flanges 101, 102 and the corresponding first end walls 103, 104 are connected via ridges 131, 138. Each of the first end walls 103, 104 and the first side wall 105 are connected via ridges 132, 137. The first side wall 105 and each of the convex end walls 121, 122 of the convex strip 106 are connected via ridges 133, 136. Each of the convex end walls 121, 122 of the convex strip 106 is connected to the top 123 via ridges 134, 135. Each of the ridges 131-138 is an arc-shaped portion having a predetermined radius of curvature when viewed from the front-rear direction X. This radius of curvature is preferably 5 mm to 20 mm, for example, 7 mm. By setting the radius of curvature of each ridgeline portion 131-138 to the above lower limit or more, the processing strain when the blank is pressed to form the first member 100 is small, and the plastic deformability after forming is high. Therefore, when the first member 100 is axially crushed by an impact load in the front-rear direction X, the first member 100 is less likely to crack, and the decrease in the impact energy absorption efficiency due to the axial crush of the first member 100 may be suppressed. In addition, by setting the radius of curvature of each ridgeline portion 131-138 to the above upper limit or less, the first end walls 103, 104, the first side wall 105, the convex strip end walls 121, 122 of the convex strip 106, and the top portion 123 can each have a sufficient length of a linear shape portion when viewed from the front-rear direction X. Therefore, the decrease in the impact energy absorption efficiency of the side member 2 due to irregular deformation during the axial crush of the first member 100 when an impact load acts in the front-rear direction X may be suppressed.

[0056] With the above configuration, in this embodiment, the first member 100 has eight ridges 131-138 and nine sides 101-104, 105d, 105d, 121-123 at the tip 20 of the side member 2, which is a larger number of ridges than a simple hat shape. Therefore, the first member 100 has a large deformation resistance when an impact load in the front-rear direction X acts on it and is axially crushed, and can absorb a larger amount of impact energy.

[0057] 1 to 7, the second beads 111 to 116 define positions that become the starting points of axial crushing of the side member 2 when an impact load acts along the front-rear direction X. The second beads 111 to 116 are formed by partially recessing the material of the first member 100 toward the second member 200. Note that the second beads 111 to 116 may also be formed by protruding in a direction away from the second member 200.

[0058] The second beads 111-116 are disposed in a region where the protruding strip 106 is disposed in the front-rear direction X. Specifically, in this embodiment, the second beads 111-116 are formed at a plurality of locations along the height direction Z at the location where the flat tip portion 105d of the first side wall 105 is disposed. The closer the positions of the second beads 111-116 are to the tip 20 of the side member 2, the more likely it is that axial crushing of the side member 2 will occur starting from a location closer to the tip 20 when an impact load is applied along the front-rear direction X. In this embodiment, the second beads 111-116 are formed on the ridge portions 131, 132, 134, 135, 137, and 138. The depth of each of the second beads 111-116 may or may not be the same as the depth of the first bead 107.

[0059] The second beads 111, 116 are also formed on the pair of first flanges 101, 102, and extend in a height direction Z intersecting with the front-rear direction X. As described below, the second beads 111, 116 are joined to second beads 211, 214 formed on the second flanges 201, 202 of the second member 200. The second beads 112-115 are formed in a dot shape on the ridge portions 132, 134, 135, 137, respectively.

[0060] (Second member) Next, a description will be given of the configuration of the second member 200. In this embodiment, the second member 200 has a cross section perpendicular to the front-rear direction X formed into a hat shape at least on the rear end 23 side (FIG. 6).

[0061] The second member 200 has a pair of second flanges 201, 202 joined to the first member 100, a pair of second end walls 203, 204 rising from the pair of second flanges 201, 202, a second side wall 205 disposed between the pair of second end walls 203, 204, and a recessed streak 206 provided on the second side wall 205, extending in the front-rear direction X from the tip 20 of the side member 2 in the front-rear direction X and having a recessed shape toward the first member 100. It is preferable that the second member 200 further has second beads 211-214 as in this embodiment.

[0062] In this embodiment, the pair of second flanges 201, 202 are disposed at the upper end and the lower end of the second member 200. Each of the second flanges 201, 202 extends from the pair of second end walls 203, 204 along the height direction Z, and is a portion of the side member 2 that protrudes upward and downward. The length of each of the second flanges 201, 202 in the height direction Z changes midway in the front-rear direction X, and the tip 20 side of the side member 2 is relatively short and the rear side of the side member 2 is relatively long. With this configuration, when an impact load during a frontal collision of the vehicle acts on the side member 2, the tip 20 side portion of the side member 2 including the protruding strip 106 can be preferentially axially crushed. The pair of second flanges 201, 202 are joined to the pair of first flanges 101, 102 by welding or / and adhesive, and together with the pair of first flanges 101, 102, form the joints 21, 22. A pair of second end walls 203, 204 are connected to the pair of second flanges 201, 202.

[0063] The pair of second end walls 203, 204 extend outward in the width direction Y from the corresponding second flanges 201, 202. Each second end wall 203, 204 may be parallel to the width direction Y, or may be inclined with respect to the width direction Y such that the distance between the pair of second end walls 203, 204 narrows as it moves away from the corresponding second flanges 201, 202, as in this embodiment. In this embodiment, the height Wof of each second end wall 203, 204 from the joints 21, 22 is less than the height Wif of each first end wall 103, 104 from the joints 21, 22. A second side wall 205 is connected to the pair of second end walls 203, 204.

[0064] The second side wall 205 is a portion facing outward in the width direction Y. In this embodiment, the second side wall 205 is formed by a flat portion 205a that is flat along the front-rear direction X from the tip 20 of the side member 2 to the middle of the front-rear direction X. In addition, the second side wall 205 is formed with an inclined portion 205b behind the rear end 205a1 of the flat portion 205a, and this inclined portion 205b is smoothly inclined so as to proceed toward the first member 100 as it proceeds rearward. In order to match this inclined shape, the height of the second end walls 203, 204 at the location where the inclined portion 205b is arranged becomes lower toward the rear. A part of the front side of the inclined portion 205b is aligned in the width direction Y with the inclined portion 105e of the first side wall 105 of the first member 100. A rear portion 205c, which is a portion behind the rear end 205b1 of the inclined portion 205b, is aligned with the flat portion 105a of the first side wall 105 in the width direction Y.

[0065] The recessed strip 206 is provided as a portion for increasing the number of ridges in the second member 200. The recessed strip 206 is formed from the tip 20 of the side member 2 to the rear end 23 in FIG. 2. The recessed strip 206 may extend to the rear end (not shown) of the side member 2, or may extend to a position forward of the rear end of the side member 2. In this embodiment, the recessed strip 206 is formed at least to a position where the first bead 107 is arranged in the front-rear direction X. The recessed strip 206 is formed to be recessed from the second side wall 205 toward the first member 100 side, and does not protrude from the second side wall 205 to the outside of the side member 2. As a result, the recessed strip 206 increases the number of ridges, and the dimension of the side member 2 in the width direction Y is not increased by providing the recessed strip 206, and the side member 2 can be made more compact. The recessed strip 206 is aligned with the protruding strip 106 in the width direction Y. In this embodiment, the recesses 206 are recessed to such an extent that they do not reach the space surrounded by the protrusions 106 when viewed in the front-rear direction X.

[0066] The recessed rib 206 is formed by bending the material of the second member 200, and is different from the second beads 211-214 (described later) which are formed by recessing a part of the material of the second member 200. The depth Woo of the recessed rib 206 at the tip 20 of the side member 2 is, for example, equal to or greater than the height Wif-Wifs of the protruding rib 106, and is set to, for example, 20 mm or more (approximately 32 mm). The recessed rib 206 extends rearward from the tip 20 of the side member 2 with a constant groove width (length in the height direction Z), and then the groove width once widens as it proceeds rearward, and then the groove width narrows as it proceeds rearward, and is then formed into a shape with a constant groove width.

[0067] The groove 206 has a pair of groove end walls 221, 222 connected to the second side wall 205, and a bottom 223 connected to the groove end walls 221, 222.

[0068] The pair of concave end walls 221, 222 may be parallel to the width direction Y, or, as in this embodiment, may be inclined with respect to the width direction Y so that the distance between the pair of concave end walls 221, 222 becomes narrower as the distance from the second side wall 205 increases.

[0069] The bottom portion 223 is a portion of the second member 200 that protrudes most inward in the width direction Y and is a portion that is perpendicular to the width direction Y. At the tip end 20 of the side member 2, the bottom portion 223 is disposed closer to the protruding ribs 106 of the first member 100 than the pair of second flanges 201, 202, so that the recessed ribs 206 are formed deep.

[0070] The bottom 223 has a tip portion 223a extending from the tip 20 of the side member 2 along the fore-and-aft direction X, an inclined portion 223b located rearward of the tip portion 223a and progressing toward the second side wall 205 as it proceeds rearward, and a rear portion 223c located rearward of the inclined portion 223b and parallel to the tip portion 223a.

[0071] In this embodiment, the tip portion 223a is aligned with the tip portion 105d of each branch portion 105b, 105c of the first side wall 105 in the width direction Y. The inclined portion 223b is disposed behind the rear end 223a1 of the tip portion 223a. As shown in FIG. 7, in this embodiment, the length of the inclined portion 223b in the front-rear direction X is less than the length of the inclined portion 105e of the first side wall 105, and the entire area of ​​the inclined portion 223b is aligned with the inclined portion 105e in the width direction Y. In the front-rear direction X, the rear end 223b1 of the inclined portion 223b is aligned with the rear end 205a1 of the flat portion 205a of the second side wall 205. The depth of the recessed strip 206 is constant at the tip portion 223a, and becomes shallower at the inclined portion 223b as it moves away from the tip 20 of the side member 2. In addition, the depth of the recess 206 at the rear portion 223c becomes shallower at the point where it connects to the inclined portion 205b of the second side wall 205 as it moves away from the tip 20 of the side member 2, and is constant at the point where it connects to the rear portion 205c of the second side wall 205.

[0072] The groove width Hoo (the center-to-center distance in the height direction Z of the ridge portions 234, 235) of the concave rib 206 is constant where the tip portion 223a is located, and where the inclined portion 223b is located, it gradually increases as it moves rearward at the point where it connects to the flat portion 205a of the second side wall 205, and gradually decreases as it moves rearward at the point where it connects to the front side of the inclined portion 205b of the second side wall 205, and is constant at the point where it connects to the rear side of the inclined portion 205b and also constant at the point where it connects to the rear portion 205c of the second side wall 205.

[0073] The above-mentioned portions of the second member 200 are connected via a plurality of ridges 231-238.

[0074] Specifically, the second flanges 201, 202 and the corresponding second end walls 203, 204 are connected to each other via ridges 231, 238. The second end walls 203, 204 and the second side wall 205 are connected to each other via ridges 232, 237. The second side wall 205 and the groove end walls 221, 222 of the groove 206 are connected to each other via ridges 233, 236. The groove end walls 221, 222 of the groove 206 are connected to the bottom 223 by ridges 234, 235. The ridges 231-238 are arc-shaped portions having a predetermined radius of curvature when viewed from the front-rear direction X. This radius of curvature is preferably 5 mm to 20 mm, for example, 7 mm. The significance of the lower and upper limits of the radius of curvature of each of the ridge lines 231 to 238 is the same as that of the lower and upper limits of the radius of curvature of each of the ridge lines 131 to 138 of the first member 100 .

[0075] With the above configuration, in this embodiment, the second member 200 has eight ridges 231-238 and nine sides 201-204, 205a, 205a, 221-223 at the tip 20 of the side member 2, which is a larger number of ridges than a simple hat shape. Therefore, like the first member 100, the second member 200 has a large deformation resistance when an impact load in the front-rear direction X acts on it and it is axially crushed, and can absorb a larger amount of impact energy.

[0076] The second beads 211-214, like the second beads 111-116 of the first member 100, are portions that determine the positions that become the starting points of axial crushing of the side member 2 when an impact load is applied in the front-rear direction X. The second beads 211-214 are formed by partially forming the material of the second member 200 into a convex or concave shape.

[0077] The second beads 211-214 are arranged in the region where the convex streak 106 is arranged in the front-rear direction X. Specifically, in this embodiment, the second beads 211-214 are aligned with the second beads 111-116 of the first member 100 in the front-rear direction X. The second beads 211-214 are formed at a plurality of locations along the height direction Z. In this embodiment, the second beads 211-214 are formed on the pair of second flanges 201, 202 and ridges 231, 238 of the second member 200, and on ridges 233, 236 connecting the flat parts 205a, 205a of the second side wall 205 and the concave streak end walls 221, 222. The depth of each of the second beads 211-214 may be the same as the depth of the second beads 111-116 of the first member 100, or may not be the same.

[0078] The second beads 211, 214 are formed on the second flanges 201, 202 and the ridge portions 231, 238, and extend in a direction intersecting the front-rear direction X. The second beads 211, 214 are overlapped and joined to the second beads 111, 116 of the first member 100. In this embodiment, the second beads 213, 214 are formed in a dot shape on the ridge portions 234, 235, respectively.

[0079] (Preferable dimensional relationship between the first member and the second member)

[0080] At the tip of the first member 100 and the tip of the second member, that is, at the tip 20 of the side member 2, the height Wif of the first member 100 from the joints 21, 22 in the width direction Y is higher than the height Wof of the second member 200 from the joints 21, 22. Note that the height Wif of the first member 100 refers to the height in the width direction Y from the joints 21, 22 to the top 123 of the rib 106. The height Wof of the second member 200 refers to the height in the width direction Y from the joints 21, 22 to the second side wall 205. By setting such a height relationship, in a cross-section orthogonal to the front-rear direction X, the line length of the first member 100 (the length when the first member 100 is regarded as a single line) can be made longer than the line length of the second member 200 (the length when the second member 200 is regarded as a single line). As a result, by providing the rib 106 on the first member 100, the strength against the impact load in the front-rear direction X can be made higher. Thereby, the effect of improving the impact energy absorption amount by providing the rib 106 can be made higher.

[0081] Also, at the tip 20 of the side member 2, the height Wif - Wifs of the rib 106 along the width direction Y is preferably 15 mm or more. Thereby, the height of the rib 106 can be sufficiently ensured, so that the strength against the impact load during a frontal collision in the rib 106 can be increased. Therefore, the impact energy absorption efficiency by the rib 106 can be increased.

[0082] Also, at the tip 20 of the side member 2, the ratio Wifs / Wif of the height Wifs of the first end walls 103, 104 to the height Wif of the first member 100 is preferably 0.4 < Wifs / Wif < 0.6. By setting 0.4 < Wifs / Wif, the height of the first end walls 103, 104 can be sufficiently ensured, and the strength of the first end walls 103, 104 against the impact load during a frontal collision can be increased. Therefore, the impact energy absorption efficiency of the side member 2 can be made higher. Also, by setting Wifs / Wif < 0.6, the strength of the first end walls 103, 104 and the strength of the rib 106 against the impact load during a frontal collision can be balanced, and a higher impact energy absorption efficiency can be realized for the entire first member 100.

[0083] In addition, at the tip 20 of the side member 2, the depth Woo of the concave strip 206 of the second member 200 is preferably 15 mm or more. By setting the depth Woo of the concave strip 206 to 15 mm or more, for example, about 20 mm, the shape around the concave strip 206 when viewed from the front-rear direction X can be made less flat. Therefore, the strength of the second member 200 against the impact load during a frontal collision can be increased.

[0084] Furthermore, at the tip 20 of the side member 2, the ratio Hoo / Woo of the width Hoo of the concave stripe 206 of the second member 200 to the depth Woo of the concave stripe 206 is preferably Hoo / Woo≦1.5. By satisfying Hoo / Woo≦1.5, the strength of the second member 200 against the impact load during a frontal collision can be increased at the tip 20 of the side member 2. Therefore, the strength of the second member 200 against the impact load during a frontal collision can be increased.

[0085] (Suspension tower) As clearly shown in Fig. 6, the suspension tower 3 is an example of another vehicle body member joined to the side member 2. Examples of the other vehicle body member include frame members and panel members such as a subframe and a bulkhead. The suspension tower 3 is provided on a vehicle having a strut-type suspension structure or a multi-link-type suspension structure.

[0086] The suspension tower 3 is, for example, a thin plate member made of the same material as the side member 2. The suspension tower 3 has a lower portion 3a joined to the flat portion 105a of the first side wall 105 of the first member 100 and / or the periphery of the flat portion 105a, and an upper portion 3b extending upward from the lower portion 3a toward the outside of the vehicle body 1 in the width direction Y. The upper portion 3b is configured to receive an upper end portion of a shock absorber (not shown). The lower end portion of the shock absorber is connected to a knuckle arm or a link arm (not shown), or the like.

[0087] (An example of the deformation of a side member during a frontal collision) In a vehicle equipped with the side member 2 having the above-mentioned configuration, when a frontal collision occurs and a certain or greater impact load acts on the side member 2, the side member 2 buckles from the location where the second beads 111-116, 211-214 are formed near the tip 20 of the side member 2, and the side member 2 plastically deforms in an accordion-like shape while being axially crushed from the tip 20 side portion of the side member 2 toward the rear. At this time, since the side member 2 is provided with the convex ribs 106 and the concave ribs 206 and has high strength, it can efficiently absorb the impact load by plastic deformation. At this time, the portion of the side member 2 where the first bead 107 is formed is suppressed from being axially crushed while the front portion where the first bead 107 is not formed is being axially crushed due to the stiffening effect of the first bead 107. In addition, in the case where an impact load still acts on the side member 2 even after the portion where the first bead 107 is not formed is sufficiently axially crushed, the portion where the first bead 107 is formed is axially crushed while generating high deformation resistance, thereby absorbing the impact load.

[0088] (Example of effect of the embodiment) As described above, in the tip 20 of the side member 2, compared to the case where the first side wall 105 does not have the protruding strip 106, the first member 100 additionally has the ridges 134, 135 which are the boundaries between the top 123 of the protruding strip 106 and the pair of protruding strip end walls 121, 122, and the ridges 133, 136 which are the boundaries between the protruding strip end walls 121, 122 and the first side wall 105. Therefore, the strength of the first member 100 against the impact load at the time of a frontal collision of the vehicle is high. Therefore, the impact energy absorption efficiency can be increased when the side member 2 is plastically deformed so as to be axially crushed by the impact load. In addition, the first side wall 105 has a shape which is gradually inclined so as to be flush with the top 123 as it proceeds from the tip 20 of the side member 2 in the front-rear direction X. Therefore, there is no portion where the shape suddenly changes between the first side wall 105 and the protruding strip 106, and the impact force along the front-rear direction X is not converted into bending force midway along the front-rear direction X. Therefore, the efficiency of absorbing impact energy by axial crushing of the side member 2 can be increased, and the collision safety performance of the vehicle can be improved. Furthermore, the first side wall 105 is formed with the first bead 107 extending in the front-rear direction X at a portion flush with the apex 123. In the side member 2, the portion where the first bead 107 is formed has a high strength along the front-rear direction X and is less likely to be axially crushed than the portion where the first bead 107 is not formed. Therefore, in the side member 2, the tip side where the first bead 107 is not formed, i.e., the tip side portion of the protruding strip 106, is preferentially plastically deformed during impact absorption, and the impact load can be absorbed by the side member 2. As a result, the side member 2 can be plastically deformed (axially crushed) more reliably and more greatly during a vehicle collision, and the impact energy absorption efficiency by the side member 2 can be increased. Furthermore, in the side member 2, a wide flat portion is secured on the surface of the first side wall 105 around the area where the first bead 107 is formed. By providing this wide flat area, a wide area can be secured for fixing other body parts of the body 1, such as the suspension tower 3, by welding or bonding. This can further improve the attachability of other body parts to the body 1. In this case, "attachability" includes at least one of the following: a high degree of design freedom in selecting the location where a part is to be attached, and the ease of installation work when installing a part.In particular, in this embodiment, the cross-sectional shape of the portion of the side member 2 where the first bead 107 is formed, which is perpendicular to the front-rear direction X, is close to a rectangular cross-sectional shape that is used in relatively many vehicle bodies. Therefore, the suspension tower 3 used in past vehicle models can be attached to the side member 2 without significantly changing its shape.

[0089] In particular, according to this embodiment, the tip 107a of the first bead 107 is disposed at the apex 123 of the protruding strip 106. With this configuration, when an impact load due to a frontal collision of the vehicle acts on the side member 2, the portion of the protruding strip 106 where the first bead 107 is not formed can be preferentially crushed in the axial direction, and the side member 2 can be plastically deformed to a greater extent from the initial stage of the start of axial crushing of the side member 2, thereby making it possible to increase the impact energy absorption efficiency. In addition, since the strength of the portion of the protruding strip 106 where the first bead 107 is formed can be increased, the impact energy absorption efficiency can be increased when that portion is axially crushed.

[0090] Moreover, according to this embodiment, at the tip 20 of the side member 2, compared to a case where the groove 206 is not formed in the second side wall 205, ridges 234, 235 which are boundaries between the bottom 223 of the groove 206 and the pair of groove end walls 221, 222, and ridges 233, 236 which are boundaries between the groove 206 and the second side wall 205 are additionally present. Therefore, the strength of the second member 200 against the impact load at the time of a frontal collision of the vehicle is high. Therefore, it is possible to further increase the efficiency of absorbing the impact energy when the side member 2 is axially crushed by the impact load.

[0091] In addition, according to this embodiment, the recessed strip 206 of the second member 200 includes an inclined portion 223b that becomes shallower as it moves away from the tip 20 of the side member 2 in the front-rear direction X. With this configuration, the recessed strip 206 gradually changes in shape as it moves rearward. Therefore, there is no portion where the shape suddenly changes between the second side wall 205 and the recessed strip 206, and the impact load along the front-rear direction X is not converted into bending force midway in the front-rear direction X. Therefore, it is possible to suppress a decrease in impact energy absorption efficiency caused by a decrease in the amount of plastic deformation of the second member 200 due to bending force. Therefore, it is possible to further increase the impact energy absorption efficiency of the side member 2.

[0092] Moreover, according to this embodiment, the second beads 111-116, 211-214 are provided on the first member 100 and the second member 200, respectively. With this configuration, when an impact load during a frontal collision acts on the side member 2, the side member 2 buckles from the locations where the second beads 111-116, 211-214 are formed near the tip 20 of the side member 2. This allows the axial crushing to be preferentially performed on the locations of the side member 2 where the convex ribs 106 and the concave ribs 206, which have a high impact energy absorption efficiency, are arranged. This allows the impact energy absorption efficiency of the side member 2 to be further increased.

[0093] According to this embodiment, the second beads 111, 116, 211, 214 are formed on the first flanges 101, 102 and the second flanges 201, 202 in the region where the protruding strip 106 is arranged in the front-rear direction X. According to this configuration, the deformation starting points of the first flanges 101, 102 and the second flanges 201, 202 when an impact load during a frontal collision of the vehicle acts on the side member 2 can be set to the locations where the second beads 111, 116, 211, 214 are arranged, and the axial crushing operation of the side member 2 can be more reliably performed as desired. Furthermore, the first flanges 101, 102 and the second flanges 201, 202 are firmly joined by the second beads 111, 116, 211, 214. Therefore, when the side member 2 is axially crushed, the first flanges 101, 102 and the second flanges 201, 202 are deformed out-of-plane in the same direction. That is, it is possible to suppress out-of-plane deformation in opposite directions so as to cause the first flanges 101, 102 and the second flanges 201, 202 to peel off from each other. This makes it possible to suppress a decrease in impact energy absorption efficiency caused by the first flanges 101, 102 and the second flanges 201, 202 peeling off from each other.

[0094] The embodiment of the present disclosure has been described above. However, the present disclosure is not limited to the above embodiment. The present disclosure can be modified in various ways within the scope of the claims. In the following, configurations different from the above embodiment will be mainly described, and similar configurations will be denoted by similar reference numerals and detailed description will be omitted.

[0095] In the above embodiment, the first bead 107 extends to the apex 123 of the protruding strip 106. However, this is not necessarily the case. For example, the tip 107a of the first bead 107 may be disposed at a location (the tip 105a1 of the flat portion 105a) where the first side wall 105 and the apex 123 are flush with each other in the front-rear direction X.

[0096] The number of second beads of the first member 100 may be more or less than that of the above-mentioned embodiment. Similarly, the number of second beads of the second member 200 may be more or less than that of the above-mentioned embodiment. In addition, at least one of the second beads of the first member 100 and the second beads of the second member 200 may be omitted.

[0097] In the above embodiment, the second beads 111-116, 211-214 are defined as the portions that serve as the starting points for the initiation of axial crushing in the side member 2 due to the impact load during a vehicle frontal collision, but this is not necessarily the case. Instead of the second beads 111-116, 211-214, a through hole may be provided in the first member 100 and / or the second member 200. In this case, the portions that serve as the starting points for the initiation of axial crushing in the side member 2 due to the impact load during a vehicle frontal collision are the portions in which the through holes are formed.

[0098] In the above-described embodiments, the second member 200 is generally hat-shaped in a cross section perpendicular to the front-rear direction X, but this is not essential. The second member 200 may have another shape, such as a straight flat plate shape in the height direction Z in a cross section perpendicular to the front-rear direction X.

[0099] In each of the above-described embodiments, the side member 2 is a front side member, but this need not be the case. The side member of the present disclosure may be a rear side member installed at the rear of the cabin. When the side member of the present disclosure is a rear side member, the tip 20 of the side member 2 is the rear end of the vehicle body 1. When the side member of the present disclosure is a rear side member, the orientation of the side member as viewed from the front-rear direction X may differ, for example, by 90 degrees or 180 degrees from the orientation of the side member when described as a front side member. EXAMPLES

[0100] Next, an embodiment of the present disclosure will be described. The conditions in the embodiment are an example of conditions adopted to confirm the feasibility and effects of the present disclosure, and the present disclosure is not limited to this example of conditions. The present disclosure may adopt various conditions as long as they do not deviate from the gist of the present disclosure and achieve the purpose of the present disclosure.

[0101] In the present disclosure, models of the side members 2 of Examples 1 to 7 and the Comparative Example were created by computer.

[0102] (Configuration of the first member common to Examples 1 to 7) Material of the first member 100: Steel plate The thickness of the first member 100 is 1.4 mm. Tensile strength of the first member 100: 1180 MPa Total length of the first member 100 in the front-rear direction X: 400 mm Length of the tip 105d (flat portion) of the first side wall 105 of the first member 100 on the tip 20 side of the side member 2: 50 mm Distance from the tip 20 of the side member 2 to the center of each of the second beads 111 to 116: 25 mm Angle range in which the ridges 131 to 138 at the tip 20 of the side member 2 are arranged as viewed from the front-rear direction X: 115 deg. Radius of curvature of each ridge 131-138 at the tip 20 of the side member 2 as viewed from the front-rear direction X: 7 mm Length in the height direction Z between the two most distant ridges 131, 138: 150 mm At the tip 20 of the side member 2, the distance in the height direction Z between the first flange 101 and the protruding strip 106: 43 mm Height of the first member 100 in the width direction Y: 60 mm At the tip 20 of the side member 2, the length of the first end walls 103, 104 in the width direction Y: 30 mm At the tip 20 of the side member 2, the length of the protruding strip 106 in the width direction Y: 30 mm

[0103] (Configuration of the second member common to Examples 1 to 7) Material of the second member 200: Steel plate The thickness of the second member 200 is 1.4 mm. Tensile strength of second member 200: 1180 MPa Total length of the second member 200 in the front-rear direction X: 400 mm Distance from the tip 20 of the side member 2 to the center of each of the second beads 211 to 214: 25 mm Angle range in which the ridges 234, 235 connecting the bottom 223 of the groove 206 at the tip 20 of the side member 2 and the groove end walls 221, 222 are disposed as viewed from the front-rear direction X: 105 deg. An angle range in which each of the ridge lines 231 to 238 at the tip 20 of the side member 2, except for the ridge lines 234 and 235, is arranged as viewed from the front-rear direction X: 115 deg. Radius of curvature of each ridge line 231-238 at the tip 20 of the side member 2 as viewed from the front-rear direction X: 7 mm Length in the height direction Z between the two most distant ridges 231, 238: 150 mm At the tip 20 of the side member 2, the height of the second member 200 in the width direction Y: 20 mm At the rear end 23 of the side member 2, the height of the second member 200 in the width direction Y: 10 mm

[0104] (First bead of Example 1) The first bead 107 in Example 1 has a tip 107a disposed 50 mm forward in the front-rear direction X from a point (tip 105a1 of flat portion 105a) where the first side wall 105 and the apex 123 are flush with each other, and has a length of 100 mm in the front-rear direction X from this point rearward to the rear end 23 of the side member 2. That is, the first bead 107 is formed on the protruding strip 106 in addition to the flat portion 105a of the first side wall 105. The width (length in the height direction Z) and depth of the first bead 107 are both 10 mm.

[0105] (First bead of Example 2) The first bead 107 in Example 2 has a tip 107a disposed 100 mm forward in the fore-aft direction X from a point (tip 105a1 of flat portion 105a) where the first side wall 105 and the apex 123 are flush with each other, and has a length of 150 mm in the fore-aft direction X from this point rearward to the rear end 23 of the side member 2. That is, the first bead 107 is formed on the protruding strip 106 in addition to the flat portion 105a of the first side wall 105. The width (length in the height direction Z) and depth of the first bead 107 are both 10 mm.

[0106] (First bead of Example 3) The first bead 107 in Example 3 has a tip 107a disposed 150 mm forward in the fore-aft direction X from a point (tip 105a1 of flat portion 105a) where the first side wall 105 and the top portion 123 are flush with each other, and has a length of 200 mm in the fore-aft direction X from this point rearward to the rear end 23 of the side member 2. That is, the first bead 107 is formed on the protruding strip 106 in addition to the flat portion 105a of the first side wall 105. The width (length in the height direction Z) and depth of the first bead 107 are both 5 mm.

[0107] As is clear from the above explanation, the first bead 107 of Example 2 is a more elongated version of the first bead 107 of Example 1, and the first bead 107 of Example 3 is a more elongated version of the first bead 107 of Example 2.

[0108] (Configuration of Comparative Example) As shown in FIG. 8, which is a perspective view of the comparative example, the comparative example does not include the first bead 107, the convex rib 106, and the concave rib 206. More specifically, in the comparative example, the side member is formed by the first member 100' and the second member 200'. Each of the members 100', 200' has a cross section perpendicular to the front-rear direction X formed in a hat shape. The first member 100' has a pair of first flanges 101, 102, a pair of end walls 103', 104', and a side wall 105'. In the first member 100', the first side wall 105' is formed by a flat portion perpendicular to the width direction Y. In addition, the second member 200' has a pair of first flanges 201, 202, a pair of end walls 203', 204', and a side wall 205'. In the second member 200', the second side wall 205' is formed by a flat portion perpendicular to the width direction Y. Also, the second beads 111, 116, 211, and 214 are formed on the first flanges 101 and 102 and the second flanges 201 and 202, and no other second beads are present. The other configurations are the same as those of the first embodiment.

[0109] (Evaluation Methods for Examples 1 to 3 and Comparative Examples) The weights of Examples 1 to 3 and the Comparative Example were measured on a computer, and the weights of Examples 1 to 3 were calculated when the weight of the Comparative Example was set to 1. Furthermore, by computer simulation, the side members of Examples 1 to 3 and the Comparative Example were axially crushed (plastically deformed to buckle like bellows) with the tip of the side member as the point of application of a load so that the overall length of the side member was shortened by 100 mm. The amount of energy absorbed by the side member at this time was calculated with the Comparative Example set to 1. The results are shown below. Weight ratio and energy absorption ratio of the comparative example: 1.00, 1.00 Weight ratio and energy absorption ratio of Example 1: 0.92, 1.02 Weight ratio and energy absorption ratio of Example 2: 0.90, 1.37 Weight ratio and energy absorption ratio of Example 3: 0.90, 1.36

[0110] As is clear from the above results, it was demonstrated that Examples 1 to 3, by providing the ridges 106, the grooves 206, and the first beads 107, can absorb more energy while reducing the mass compared to the comparative example, and have excellent impact energy absorption efficiency. In particular, as is clear from Examples 2 and 3, by extending the first bead 107 from the flat portion 105a of the first side wall 105 forward to the ridges 106 by more than 50 mm, it was possible to improve the energy absorption ratio by nearly 40%, demonstrating that the impact energy absorption efficiency is extremely excellent.

[0111] (Configuration of Examples 4 and 5) The first beads in Examples 4 and 5 are similar to Example 3. The width Hoo of the concave stripe 206 at the tip 20 of the side member 2 in Example 4 is 36 mm. The width Hoo of the concave stripe 206 at the tip 20 of the side member 2 in Example 5 is 28 mm. The depth Woo of the concave stripe 206 at the tip 20 of the side member 2 in Examples 4 and 5 is both 20 mm. Therefore, the ratio Hoo / Woo of the width Hoo to the depth Woo of the concave stripe 206 is 1.8 (more than 1.5) in Example 4 and 1.4 (1.5 or less) in Example 5.

[0112] (Evaluation methods for Examples 4 and 5) The evaluation methods for Examples 4 and 5 were the same as those for Examples 1 to 3 and the Comparative Example, except that the weight ratio and energy absorption ratio for Example 4 were both set to 1.00. The results are shown below. Weight ratio and energy absorption ratio of the comparative example: 1.11, 0.80 Weight ratio and energy absorption ratio of Example 4: 1.00, 1.00 Weight ratio and energy absorption ratio of Example 5: 1.00, 1.14

[0113] As is clear from the above results, it was demonstrated that Examples 4 and 5 can absorb more energy while reducing the mass compared to the comparative example, and have excellent impact energy absorption efficiency. In particular, as is clear from Example 5, it was demonstrated that by setting the ratio Hoo / Woo of the width Hoo and the depth Woo of the groove 206 to 1.5 or less, the depth of the groove 206 can be sufficiently secured, and the energy absorption ratio can be clearly increased. In this way, it was demonstrated that the strength against impact loads can be increased by providing the groove 206, and excellent impact energy absorption efficiency is achieved.

[0114] (Configuration of Examples 6 and 7) The first beads of Example 6 and Example 7 are similar to Example 3. The second beads 212, 213 of the second member 200 of Example 6 are not dot-like, but are formed over the entire area in the height direction Z on the corresponding flat portions 205a, 205a of the second side wall 205. Example 7 differs from Example 6 in that, in addition to the configuration of Example 6, second beads having the same shape as the second bead 212 are added to the flat portions 205a, 205a of the second side wall 205 at a pitch (center-to-center distance) of 40 mm behind the second bead 212, and further, second beads having the same shape as the second bead 213 are added at a pitch of 40 mm behind the second bead 213.

[0115] The evaluation methods for Examples 6 and 7 were the same as those for Examples 1 to 3 and the Comparative Example, except that the weight ratio and energy absorption ratio were both set to 1.00 in Example 6. The results are shown below. Weight ratio and energy absorption ratio of the comparative example: 1.11, 0.88 Weight ratio and energy absorption ratio of Example 6: 1.00, 1.00 Weight ratio and energy absorption ratio of Example 7: 1.00, 1.11

[0116] As is clear from the above results, Examples 6 and 7 are able to absorb more energy while reducing the mass compared to the comparative example, and are proven to have excellent impact energy absorption efficiency. In particular, as is clear from Example 7, by providing a plurality of second beads at intervals in the front-rear direction X, each portion on the tip 20 side of the side member 2 can be plastically deformed into a more fine bellows-like shape by the impact load. Therefore, it is proven to have excellent impact energy absorption efficiency. [Industrial Applicability]

[0117] The present invention can be applied to a side member and a vehicle body including the side member. [Explanation of symbols]

[0118] 1. Vehicle body 2 Side members 3 Suspension tower (body component) 21,22 Joint 100 First member 101, 102 A pair of first flanges 103, 104 A pair of first end walls 105 First side wall 105e Inclined portion (a portion extending so as to approach the top of the convex strip as it moves away from the tip of the first member) 106 Convex strip 107 First bead (bead) 107a Bead tip 111~116 2nd bead 200 Second member 201, 202 A pair of second flanges 203, 204 A pair of second end walls 205 Second side wall 206 Concave line 211~214 2nd bead 223b Inclined portion (part that becomes shallower as it moves away from the tip of the second member) X Anteroposterior direction

Claims

1. A side member extending in a front-rear direction of a vehicle, A first member having a hat-shaped cross section perpendicular to the front-rear direction; A second member joined to the first member and cooperating with the first member to form a closed cross-sectional shape; Equipped with the first member includes a pair of first end walls rising from a joint portion with the second member, a first side wall disposed between the pair of first end walls, and a convex strip provided on the first side wall, extending in the front-rear direction from a tip of the first member in the front-rear direction and having a shape convex in a direction away from the second member, the first side wall has a portion extending in the front-rear direction so as to approach the apex of the protrusion as it moves away from the tip of the first member, and is flush with the apex at a midpoint in the front-rear direction; A bead is formed on the first side wall at a location flush with the top portion, the bead extending in the front-rear direction, the second member includes a pair of second end walls rising from a joint portion with the first member, and a second side wall disposed between the pair of second end walls, A side member, wherein the second member has a recess formed on the second side wall, extending in the fore-and-aft direction from a tip of the second member in the fore-and-aft direction and recessed toward the first member.

2. 2. The side member according to claim 1, wherein a tip of the bead is disposed on the apex at a location where the first side wall and the apex are flush with each other in the fore-and-aft direction, or at a location moving from the location toward the tip of the first member.

3. The side member according to claim 1 , wherein the recess includes a portion that becomes shallower as it moves away from the tip of the second member in the front-rear direction.

4. 2. The side member according to claim 1, wherein at a tip of the first member and a tip of the second member in the fore-and-aft direction, a height of the first member from the joint portion is greater than a height of the second member from the joint portion.

5. The side member according to claim 1 , wherein each of the first member and the second member is provided with a second bead extending in a direction intersecting the front-rear direction.

6. the first member includes a pair of first flanges extending from the pair of first end walls; the second member includes a pair of second flanges joined to the pair of first flanges and constituting the joint portion together with the pair of first flanges, The side member according to claim 5 , wherein the second bead is formed on the first flange and the second flange in a region where the protruding strip is arranged in the front-rear direction.

7. A vehicle body comprising: the side member according to any one of claims 1 to 6; and a vehicle body member joined to the first member of the side member.

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