Side sill structure

Abstract

This side sill structure comprises: a side sill member 1; a stiffener 2 disposed in an internal space 1S thereof; and a body outer panel 3O and a body inner panel 3I sandwiching the side sill member 1. The side sill member 1 is formed by welding a sill outer panel 1O and a sill inner panel 1I. The stiffener 2 has an inverted U-shaped cross section and is attached to the inner surface of the internal space 1S across an upper joining edge 1U of the side sill member 1. In the entire area of a closed space 3S formed by the body outer panel 3O and the body inner panel 3I, the upper joining edge 1U forms a non-welding area 5 in which an upper edge 1OU of the sill outer panel 1O and an upper edge 1IU of the sill inner panel 1I are not welded. The stiffener 2 is disposed so as to overlap the non-welding area 5 in plan view, and is welded to the sill outer panel 1O and fastened to the sill inner panel 1I by fasteners 6B, 6N.

Description

Side sill structure

[0001] The present invention relates to a side sill structure for a vehicle.

[0002] Vehicles such as passenger cars are equipped with side sill members at the bottom of each side of the vehicle body. The side sill members extend in the longitudinal direction of the vehicle from just behind the front wheels to just in front of the rear wheels. The side sill members are formed by joining a sill outer panel having a hat-shaped cross section with a sill inner panel also having a hat-shaped cross section. When joining them, the upper flange of the sill outer panel is welded to the upper flange of the sill inner panel. Similarly, the lower flange of the sill outer panel is welded to the lower flange of the sill inner panel. The welding may be spot welding or laser welding. Patent Document 1 discloses a side sill structure having the above-mentioned structure.

[0003] Japanese Patent Application Laid-Open No. 2019-151297

[0004] The side sill member also has a portion that is sandwiched between a body inner panel and a body outer panel from the outside. For example, in the portion facing the front wheelhouse below the A-pillar, the front end of the side sill member is sandwiched between an A-pillar outer panel and an A-pillar inner panel that extend downward from the bottom end of the A-pillar. Here, when assembling the vehicle body, the sill outer panel is welded to the A-pillar outer panel in advance, and the sill inner panel is welded to the A-pillar inner panel in advance. The sill outer panel and the A-pillar outer panel are then welded to the sill inner panel and the A-pillar inner panel.

[0005] At this time, the flange of the sill outer panel and the flange of the sill inner panel are welded to form a side sill member with a closed cross section. The A-pillar outer panel and the A-pillar inner panel are also welded. However, because the front end of the side sill member is located within the closed space formed by the joining of the A-pillar outer panel and the A-pillar inner panel, the upper flanges of the sill outer panel and the sill inner panel cannot be welded together within this closed space. However, the lower flanges of the sill outer panel and the sill inner panel are not located within the closed space and are exposed to the underside of the vehicle floor, so they can be welded.

[0006] If the upper flanges of the sill outer panel and the sill inner panel are not joined together within the closed space described above, the strength and rigidity of the side sill member, which is a skeletal structural member of the vehicle body, will be reduced.

[0007] An object of the present invention is to provide a side sill structure that can suppress a decrease in the strength and rigidity of the side sill member.

[0008] A side sill structure according to one aspect of the present invention includes a side sill member, a stiffener disposed in the interior space of the side sill member, and a body outer panel and a body inner panel sandwiching the side sill member. The side sill member is formed by welding the sill outer panel and the sill inner panel together. The stiffener has an inverted U-shaped cross section and is attached to the inner surface of the side sill member, straddling the upper joint edge of the side sill member. Throughout the enclosed space formed by the body outer panel and the body inner panel, the upper joint edge forms a non-welded area where the upper edge of the sill outer panel and the upper edge of the sill inner panel are not welded. The stiffener is disposed so as to overlap the non-welded area in a plan view, and is welded to one of the sill outer panel and the sill inner panel and fastened to the other with a fastener.

[0009] According to the side sill structure according to one aspect of the present invention, it is possible to suppress a decrease in the strength and rigidity of the side sill member.

[0010] FIG. 1 is a cross-sectional view of a side sill structure according to an embodiment. FIG. 2 is a perspective view showing the exterior of the side sill structure. FIG. 3A is a perspective view of a stiffener of the side sill structure. FIG. 3B is a side view of the stiffener. FIG. 4 is a perspective view showing the stiffener joined to a reinforcement member. FIG. 5 is an exploded side view of the side sill structure (first state). FIG. 6A is an exploded perspective view of the side sill structure (second state). FIG. 6B is a side view of the second state. FIG. 7A is an exploded perspective view of the side sill structure (third state). FIG. 7B is a side view of the third state. FIG. 8A is an exploded perspective view of the side sill structure (fourth state). FIG. 8B is a side view of the fourth state. FIG. 9 is a side view of the side sill structure (fifth state).

[0011] Hereinafter, a side sill structure according to an embodiment will be described with reference to the drawings. Note that Figures 1 to 9 refer to the present embodiment and show a side sill structure constructed on the left side of a vehicle, and a side sill structure is also constructed symmetrically on the right side of the vehicle.

[0012] First, an overview of the side sill structure according to the embodiment will be described with reference to Figures 1 and 2. Figure 1 is also a cross-sectional view taken along line I-I in Figures 5 and 9, and is a cross-sectional view of a non-welded region 5, which will be described later. In a vehicle such as a passenger car, a side sill member 1 is provided at the bottom of each of both sides of the vehicle body. The side sill member 1 extends in the longitudinal direction of the vehicle from immediately behind the front wheels to immediately in front of the rear wheels. The side sill structure according to the embodiment is provided at the front end of the side sill member 1, and its front end reaches the front wheel housing WH (see Figure 2) for the front wheels.

[0013] The side sill member 1 is formed by welding both side edges (upper edge 1OU and lower edge 1OL) of the sill outer panel 1O to both side edges (upper edge 1IU and lower edge 1IL) of the sill inner panel 1I. The sill outer panel 1O is a pressed steel plate product and has a hat-shaped cross section. The upper edge 1OU and lower edge 1OL of the sill outer panel 1O are formed as flanges. Hereinafter, the upper edge 1OU and lower edge 1OL of the sill outer panel 1O are also referred to as upper flange 1OU and lower flange 1OL, respectively. Similarly, the sill inner panel 1I is also a pressed steel plate product and has a hat-shaped cross section. The upper edge 1IU and lower edge 1IL of the sill inner panel 1I are also formed as flanges. Hereinafter, the upper edge 1IU and lower edge 1IL of the sill inner panel 1I are also referred to as upper flange 1IU and lower flange 1IL, respectively.

[0014] The upper flanges 1OU and 1IU are spot-welded to each other along the entire length of the side sill member 1, forming the upper joint edge 1U of the side sill member 1. However, as will be described later, there are portions of the upper joint edge 1U that cannot be spot-welded due to their relationship with other components. On the other hand, the lower flanges 1OL and 1IL are also spot-welded to each other along the entire length of the side sill member 1, forming the lower joint edge 1L of the side sill member 1. Because the lower flanges 1OL and 1IL are exposed to the underside of the vehicle floor, they can be welded along the entire length of the side sill member 1. These spot welds also spot-weld the body side panel 8, which will be described later. In other words, the side sill member 1 is formed by welding together both side edges 1OU and 1OL of the sill outer panel 1O and both side edges 1IU and 1IL of the sill inner panel 1I.

[0015] The front end of the side sill member 1 is sandwiched between an A-pillar outer panel 3O, which serves as a body outer panel extending downward from the lower end of the A-pillar, and an A-pillar inner panel 3I, which serves as a body inner panel. The A-pillar outer panel 3O and the A-pillar inner panel 3I are pressed steel plates. In this embodiment, the A-pillar outer panel 3O is welded to the sill outer panel 1O, and the A-pillar inner panel 3I is welded to the sill inner panel 1I and fastened together with fasteners. In this embodiment, the fasteners are bolts 6B and weld nuts 6N welded to the stiffeners 2. Furthermore, above the side sill member 1, the A-pillar outer panel 3O and the A-pillar inner panel 3I are also welded to each other.

[0016] The front end of the side sill member 1 is sandwiched between an A-pillar outer panel 3O and an A-pillar inner panel 3I, which are welded to each other, and a closed space 3S is formed by the side sill member 1, the A-pillar outer panel 3O, and the body inner panel 3I. Because a spot welder cannot be inserted into this closed space 3S, the upper edge 1OU of the sill outer panel 1O and the upper edge 1IU of the sill inner panel 1I cannot be spot welded within the closed space 3S. For this reason, the upper joint edge 1U of the side sill member 1 forms a non-welded area 5 throughout the entire closed space 3S. The order of the construction process for the side sill structure of this embodiment will be described later.

[0017] In the embodiment, the upper edge 1IU of the sill inner panel 1I does not have an upper flange in the non-welding region 5 within the closed space 3S. However, the upper edge 1IU may also have an upper flange in the non-welding region 5. Furthermore, the A-pillar outer panel 3O and the body inner panel 3I that form the closed space 3S may be formed with mounting holes for resin brackets that bundle cables and service holes for inserting hand tools. Therefore, the closed space 3S does not mean that it must be completely closed, but rather means that it is closed so that welding with a welding machine cannot be performed.

[0018] The side sill member 1 does not have a completely closed cross section in the portion where the above-mentioned non-welded region 5 is formed. Therefore, there is a concern that the strength and rigidity of the side sill member 1 may be reduced in the non-welded region 5. For this reason, in this embodiment, a stiffener 2 is provided in the internal space 1S of the side sill member 1 to suppress the reduction in strength and rigidity of the side sill member 1 in the non-welded region 5. As shown in FIG. 1 , the stiffener 2 has an inverted U-shaped cross section and is attached to the inner surface of the side sill member 1, straddling the above-mentioned upper joint edge 1U. The stiffener 2 is disposed in the internal space 1S so that at least a portion of it overlaps with the non-welded region 5 in a plan view.

[0019] The stiffener 2 is a pressed steel plate and includes an upper plate 2U, an outer plate 2O, and an inner plate 2I as shown in Figures 3A and 3B. The outer plate 2O is welded to the sill outer panel 1O and the A-pillar outer panel 3O at welding points 2P shown in Figures 1 and 3A. A pair of weld nuts 6N (6NF, 6NR) are welded to the inner surface of the inner plate 2I. Bolt holes corresponding to the weld nuts 6N are formed in the inner plate 2I (see Figure 1).

[0020] The front weld nut 6NF is located at the front of the inner plate 2I. The inner plate 2I, sill inner panel 1I, and A-pillar inner panel 3I are fastened together by the bolt 6B and weld nut 6NF. The rear weld nut 6NR is located at the rear of the inner plate 2I. The inner plate 2I, an inner reinforcement member 7I (described below), the sill inner panel 1I, and the A-pillar inner panel 3I are fastened together by the bolt 6B and weld nut 6NF. The stiffener 2 has a protruding piece 2T aligned with the position of the upper joint edge 1U described above. The protruding piece 2T extends forward and downward from the front end edge 2F of the stiffener 2.

[0021] In the vertical direction, the joint position between the stiffener 2 and the sill outer panel 1O is lower than the joint position between the stiffener 2 and the sill inner panel 1I. In other words, the weld point 2P is lower than the fastening point of the bolt 6B and the weld nut 6N. In other words, the vertical distance from the upper plate 2U to the weld point 2P is longer than the vertical distance from the upper plate 2U to the fastening point of the bolt 6B and the weld nut 6N. As will be explained in detail later, in this embodiment, a pair of reinforcement members 7 (7O, 7I) shown in FIG. 4 are also disposed in the internal space 1S of the side sill member 1. The reinforcement members 7O, 7I are pressed steel plates and are angle bars with an L-shaped cross section. The front ends of the reinforcement members 7 are joined to the rear ends of the stiffeners 2. The reinforcement members 7 extend along the extension direction of the side sill member 1.

[0022] Next, the side sill structure according to the embodiment will be described in detail, starting with the components on the vehicle interior side, with reference to Figures 5 to 9. Note that the description here does not focus on the order of steps for constructing the side sill structure, but will simply focus on the components on the vehicle interior side. The order of the construction steps will be described later.

[0023] As shown in Figure 5, the A-pillar inner panel 3I, which serves as a body inner panel, is located at the innermost position, i.e., closest to the passenger compartment. The sill inner panel 1I is fastened to the lower part of the A-pillar inner panel 3I. That is, the A-pillar inner panel 3I is disposed on the inner side in the vehicle width direction relative to the side sill member 1. A pair of bolt holes 6H for inserting bolts 6B are formed in each of the A-pillar inner panel 3I and the sill inner panel 1I.

[0024] 6A and 6B , an inner plate 2I of a stiffener 2 is fastened to a sill inner panel 1I. That is, the stiffener 2 is disposed within the internal space 1S of the side sill member 1. The stiffener 2 is contained within the non-welded region 5 described above and overlaps with the non-welded region 5. A pair of reinforcement members 7 joined to the stiffener 2 are also disposed within the internal space 1S of the side sill member 1. The pair of reinforcement members 7 are disposed at upper corners in the closed cross section of the side sill member 1.

[0025] An inner reinforcement member 7I on the inside of the vehicle is welded to the sill inner panel 1I. The front end of the inner reinforcement member 7I is also fastened together with the stiffener 2 by a weld nut 6NR on the rear side of the stiffener 2. In other words, the stiffener 2 is joined to the sill inner panel 1I (side sill member 1) with the front end of the inner reinforcement member 7I interposed therebetween. In the vertical direction, the lower end 3IL of the A-pillar inner panel 3I, which serves as a body inner panel, is positioned lower than the reinforcement member 7.

[0026] As shown in Figures 7A and 7B, the stiffener 2 and reinforcement member 7 are disposed inside the interior space 1S, and the sill outer panel 1O is joined to the sill inner panel 1I. More specifically, an upper flange 1IU of the sill inner panel 1I is spot-welded to an upper flange 1OU of the sill outer panel 1O, forming an upper joint edge 1U. Similarly, a lower flange 1IL of the sill inner panel 1I is spot-welded to a lower flange 1OL of the sill outer panel 1O, forming a lower joint edge 1L. An outer reinforcement member 7O on the outside of the vehicle is welded to the sill outer panel 1O. The front end of the outer reinforcement member 7O is also spot-welded to the stiffener 2. That is, the stiffener 2 is joined to the sill outer panel 1O (side sill member 1) with the front end of the outer reinforcement member 7O interposed therebetween.

[0027] As shown in Figures 8A and 8B, an A-pillar outer panel 3O serving as a body outer panel is disposed on the vehicle width direction outer side of the sill outer panel 1O. The sill outer panel 1O is spot-welded to the lower part of the A-pillar outer panel 3O. The sill outer panel 1O is spot-welded to the sill outer panel 1O and the stiffener 2 at the portion where it overlaps with the stiffener 2, i.e., the above-mentioned welding point 2P. The A-pillar inner panel 3I and the A-pillar outer panel 3O are joined to each other at their side edges, forming an enclosed space 3S therein. In the vertical direction, the lower end 2L (see Figure 1) of the outer plate 2O of the stiffener 2 is at the same height as the lower end 3OL of the A-pillar outer panel 3O serving as a body outer panel.

[0028] More specifically, a front flange 3IF of the A-pillar inner panel 3I is spot-welded to a front flange 3OF of the A-pillar outer panel 3O. Similarly, a rear flange 3IR of the A-pillar inner panel 3I is spot-welded to a rear flange 3OR of the A-pillar outer panel 3O. The lowermost ends of the rear flanges 3IR and 3OR are spot-welded with the upper joining edge 1U of the side sill member 1 sandwiched between them. In the vertical direction, the lower end 3OL of the A-pillar outer panel 3O, which serves as a body outer panel, is located below the reinforcement member 7.

[0029] The enclosed space 3S is formed between the joined front flanges 3IF and 3OF and the joined rear flanges 3IR and 3OR. As clearly shown in Figures 6A and 7A, the upper joint edge 1U forms a non-welded region 5 throughout the enclosed space 3S. In the non-welded region 5, the upper edge 1OU of the sill outer panel 1O and the upper edge 1IU of the sill inner panel 1I are not welded. The protruding piece 2T of the stiffener 2 described above is located directly below the non-welded region 5 of the upper joint edge 1U.

[0030] 9 , in this embodiment, a body side panel 8 is also disposed further outward from the A-pillar outer panel 3O. The body side panel 8 is spot-welded to the side sill member 1 at an upper joint edge 1U and a lower joint edge 1L. The body side panel 8 is also spot-welded to the A-pillar outer panel 3O and the A-pillar inner panel 3I at the front flanges 3OF and 3IF and the rear flanges 3OR and 3IR.

[0031] The process for constructing the above-described side sill structure will be briefly described. First, the outer reinforcement member 7O is spot-welded to the sill outer panel 1O. Then, the outer plate 2O of the stiffener 2 is spot-welded to the sill outer panel 1O at the welding point 2P. At this time, the sill outer panel 1O and the stiffener 2 are also spot-welded to each other at the overlapping portion between the front end of the stiffener 2 and the outer reinforcement member 7O, with the front end of the outer reinforcement member 7O sandwiched between them. Next, the front end of the sill outer panel 1O is spot-welded to the lower part of the A-pillar outer panel 3O. The sill outer panel 1O and the A-pillar outer panel 3O, which have been joined together, are then joined to the body side panel 8. However, at this point, spot welding is not performed at the flanges 10U, 10L, 30F, and 30R. In this manner, the outer panel assembly is formed.

[0032] In parallel with the formation of the outer panel assembly described above, the inner panel assembly is also formed. Specifically, the inner reinforcement member 7I is spot welded to the sill inner panel 1I. Next, the front end of the sill inner panel 1I to which the inner reinforcement member 7I is joined is spot welded to the lower part of the A-pillar inner panel 3I.

[0033] Finally, the outer panel assembly and the inner panel assembly are joined by spot welding. At this time, spot welding is performed at the flanges 10U, 1OL, 3OF, and 3OR. Because a closed space 3S is formed during this spot welding, the non-welded area 5 of the upper joint edge 1U described above becomes inaccessible. In other words, the non-welded area 5 is ultimately formed. Therefore, after joining the outer panel assembly and the inner panel assembly, bolts 6B are fastened into a pair of bolt holes 6H in the sill inner panel 1I from the inside of the vehicle cabin. The bolts 6B are threaded into weld nuts 6N of the stiffener 2, joining the sill inner panel 1I and the sill outer panel 1O via the stiffener 2 in the non-welded area 5.

[0034] The effects of the side sill structure of the embodiment will be described below.

[0035] (1) The side sill structure of this embodiment includes a side sill member 1, a stiffener 2 having an inverted U-shaped cross section, an A-pillar outer panel (body outer panel) 3O, and an A-pillar inner panel (body inner panel) 3I. The side sill member 1 is formed by welding both side edges of the sill outer panel 1O to both side edges of the sill inner panel 1I. The A-pillar outer panel 3O is disposed on the outer side of the side sill member 1 in the vehicle width direction, and the A-pillar inner panel 3I is disposed on the inner side of the side sill member 1 in the vehicle width direction. The stiffener 2 is disposed in the interior space 1S of the side sill member 1, straddling an upper joint edge 1U between the sill outer panel 1O and the sill inner panel 1I, and attached to the inner surface of the side sill member 1. The upper joint edge 1U forms a non-welded region 5 across the entire enclosed space 3S, where an upper edge 1OU of the sill outer panel 1O and an upper edge 1IU of the sill inner panel 1I are not welded. The stiffener 2 is positioned so as to overlap the non-welded region 5 in a plan view. The stiffener 2 is welded to the sill outer panel 1O and fastened to the sill inner panel 1I with fasteners (bolts 6B and weld nuts 6N). Therefore, by joining the sill outer panel 1O and the sill inner panel 1I with the stiffener 2 in the non-welded region 5 of the upper joint edge 1U in the enclosed space 3S, which is inaccessible to a welding machine, it is possible to suppress a decrease in the strength and rigidity of the side sill member 1. Suppressing a decrease in the strength and rigidity of the side sill member 1 contributes to preventing a decrease in the vehicle's crash performance and vehicle maneuverability.

[0036] (2) In the embodiment, the stiffener 2 is welded to the sill outer panel 1O and fastened to the sill inner panel 1I with fasteners (bolts 6B and weld nuts 6N). In this case, the fasteners do not protrude outward in the vehicle width direction. Furthermore, even if the stiffener 2 is fastened to the sill inner panel 1I with fasteners and the fasteners protrude into the vehicle cabin, the fasteners can be easily hidden by floor carpet or the like. Contrary to the above embodiment, if the stiffener 2 is welded to the sill outer panel 1O and fastened to the sill inner panel 1I, the fasteners may protrude outward from the vehicle body. As a result, the front fender, which is located further outward from the fasteners, may need to be positioned further outward, thereby widening the vehicle width. This does not occur in the above embodiment.

[0037] However, if no particular problem arises, the stiffener 2 may be fastened to the sill outer panel 1O with fasteners and welded to the sill inner panel 1I. That is, the stiffener 2 may be welded to one of the sill outer panel 1O and the sill inner panel 1I and fastened to the other with fasteners. Also, although the fasteners in the above embodiment are bolts 6B and weld nuts 6N, the fasteners are not limited to bolts and nuts. For example, other types of fasteners, such as rivets, may be used.

[0038] (3) Furthermore, in the embodiment, the joining position (weld point 2P) between the stiffener 2 and the sill outer panel 1O is located lower in the vertical direction than the joining position (bolt 6B and weld nut 6N) between the stiffener 2 and the sill inner panel 1I. In other words, in the cross section shown in FIG. 1 , the distance between the upper corner of the sill outer panel 1O and the weld point 2P is longer than the distance between the upper corner of the sill inner panel 1I and the bolt 6B and weld nut 6N. The corner in the cross section is a portion with high strength and rigidity. Therefore, in the above embodiment, the combined strength of the sill outer panel 1O and the stiffener 2 is weaker than the combined strength of the sill inner panel 1I and the stiffener 2. As a result, when an axial compressive load acts on the side sill member 1 during a vehicle collision, the sill outer panel 1O deforms before the sill inner panel 1I, causing the side sill member 1 to bend convexly inward in the vehicle width direction. However, this inward bending of the side sill member 1 can be absorbed by a cross member extending in the vehicle width direction on the vehicle floor. In other words, by having the cross member absorb the collision load during a vehicle collision, deformation of the side sill member 1 can be suppressed, thereby improving the vehicle's collision performance.

[0039] (4) The side sill structure of the embodiment further includes a reinforcement member 7 extending in the internal space 1S of the side sill member 1 along the extension direction of the side sill member 1. Here, the stiffener 2 is connected to the side sill member 1 with the reinforcement member 7 interposed therebetween. As shown in FIG. 1 , the stiffener 2 is disposed in the upper part of the internal space 1S. Therefore, the reinforcement member 7 is also disposed in the upper part of the internal space 1S, suppressing upward deformation of the side sill member 1. As a result, reduction in cabin space due to upward deformation of the side sill member 1 during a vehicle collision can be suppressed. Furthermore, from the internal space 1S side, the stiffener 2, at least a portion of the reinforcement member 7, and the side sill member 1 are stacked and joined in this order. Therefore, the reinforcement member 7 extending in the extension direction of the side sill member 1 is disposed above the stiffener 2, which more effectively suppresses upward deformation of the side sill member 1 at the portion where the stiffener 2 ends. In this way, the side sill member 1 can be compressed and deformed in the axial direction while being prevented from being deformed upward, thereby improving the absorption of collision energy during a vehicle collision.

[0040] (5) Furthermore, in the embodiment, the lower ends 3IL of the A-pillar outer panel (body outer panel) 3O and the A-pillar inner panel (body inner panel) 3I are positioned vertically lower than the reinforcement member 7. In other words, the A-pillar outer panel 3O and the A-pillar inner panel 3I extend downward below the reinforcement member 7. As a result, the A-pillar outer panel 3O and the A-pillar inner panel 3I are prevented from curling up during a vehicle collision, ensuring that the side sill member 1 is compressively deformed in the axial direction, thereby improving absorption of collision energy during a vehicle collision.

[0041] (6) In the embodiment, the stiffener 2 is joined to the body outer panel 3O, and the lower end 2L of the stiffener 2 on the A-pillar outer panel (body outer panel) 3O side is at the same height as the lower end 3OL of the A-pillar outer panel 3O in the vertical direction. This improves the joining strength between the stiffener 2 and the A-pillar outer panel 3O.

[0042] (7) Furthermore, in this embodiment, the stiffener 2 has a protruding piece 2T extending from a portion of its leading edge 2F corresponding to the upper joint edge 1U. The protruding piece 2T of the stiffener 2 is provided so as to cover the non-welded region 5 of the upper joint edge 1U. During a vehicle collision, a force acts on the side sill member 1, attempting to open the side sill member 1 starting from the non-welded region 5. The stiffener 2 prevents this opening, but a force acts on the stiffener 2, attempting to tear the leading edge 2F starting from the position of the protruding piece 2T corresponding to the non-welded region 5. By dispersing this tearing force with the protruding piece 2T, tearing of the leading edge 2F of the stiffener 2 is prevented, and a reduction in the strength of the side sill member 1 due to the stiffener 2 can be more reliably prevented.

[0043] (8) In the embodiment, the protruding pieces 2T extend downward. As described above, the stiffener 2 is disposed in the upper part of the internal space 1S, and the protruding pieces 2T extend downward from the stiffener 2. As a result, a ridge (bent portion) is formed between the base end of the protruding pieces 2T and the upper plate 2U. This improves the strength of the protruding pieces 2T, and more effectively disperses the tearing force caused by the protruding pieces 2T.

[0044] (9) Furthermore, in this embodiment, the closed space 3S is formed below the A-pillar and behind the front wheel house WH. That is, the side sill structure is constructed at the front end of the side sill member 1. As a result, it is possible to prevent the front end of the side sill member 1 from opening from the non-welded region 5 during a frontal collision of the vehicle. In particular, in a type of collision known as a small offset frontal collision, the front wheels often strike the front end of the side sill member 1, and the side sill structure of the above embodiment is effective in this type of collision.

[0045] The above-described embodiments are merely examples described to facilitate understanding of the invention. The technical scope of the invention is not limited to the specific technical matters disclosed in the above-described embodiments, but also includes various modifications, changes, alternative technologies, etc. that can be easily derived therefrom.

[0046] DESCRIPTION OF SYMBOLS 1 Side sill member 1U Upper joint edge 1S Internal space 1I Sill inner panel 1IU Upper flange (upper edge) 1IL Lower flange (lower edge) 1O Sill outer panel 1OU Upper flange (upper edge) 1OL Lower flange (lower edge) 2 Stiffener 2F Front edge 2L Lower edge 2T Convex piece 3I A-pillar inner panel (body inner panel) 3IL Lower edge 3O A-pillar outer panel (body outer panel) 3OL Lower edge 3S Enclosed space 5 Non-welded area 6B Bolt (fastener) 6N Weld nut (fastener) 7 Reinforcement member WH Front wheel house

Claims

1. A side sill member is formed by joining the edges of both sides of the sill outer panel and the edges of both sides of the sill inner panel by welding, A stiffener having an inverted U-shaped cross-section is disposed in the internal space of the side sill member, straddling the upper joining edge between the sill outer panel and the sill inner panel, and attached to the inner surface of the side sill member, A body outer panel positioned outward in the vehicle width direction relative to the aforementioned side sill member, A body inner panel positioned inward in the vehicle width direction relative to the side sill member, Equipped with, The aforementioned upper joining edge forms a non-welded region where the upper edge of the sill outer panel and the upper edge of the sill inner panel are not welded together, throughout the entire enclosed space formed by the side sill member, the body outer panel, and the body inner panel. The stiffener is positioned in a plan view overlapping with the non-welded area, welded to one of the sill outer panel and the sill inner panel, and fastened to the other of the sill outer panel and the sill inner panel by fasteners, in a side sill structure.

2. The side sill structure according to claim 1, wherein the stiffener is welded to the sill outer panel and fastened to the sill inner panel by the fastener.

3. The side sill structure according to claim 1 or 2, wherein, in the vertical direction, the connection position between the stiffener and the sill outer panel is lower than the connection position between the stiffener and the sill inner panel.

4. The internal space of the side sill member is further provided with a reinforcement member that extends along the direction of extension of the side sill member. The side sill structure according to claim 1 or 2, wherein the stiffener is connected to the side sill member with the reinforcement member interposed between them.

5. The side sill structure according to claim 4, wherein, in the vertical direction, the lower ends of the body outer panel and the body inner panel are located below the reinforcement member.

6. The stiffener is connected to the body outer panel, The side sill structure according to claim 5, wherein, in the vertical direction, the lower end of the stiffener on the body outer panel side is at the same height as the lower end of the body outer panel.

7. The side sill structure according to claim 1 or 2, wherein the stiffener has a protruding piece extending from the portion of its front end corresponding to the upper joining edge.

8. The side sill structure according to claim 7, wherein the convex piece extends downward.

9. The side sill structure according to claim 1 or 2, wherein the enclosed space is formed below the A-pillar and behind the front wheel house.