JP7259771B2 - vehicle side structure - Google Patents

Description

This specification discloses a vehicle side structure that includes a rocker outer reinforcement that extends in the longitudinal direction of the vehicle.

In general, rocker outer reinforcements (hereinafter referred to as “rocker outer R/F”) extending in the longitudinal direction of the vehicle are provided below the floor of the vehicle and near both ends in the vehicle width direction. The Rocker Outer R/F is designed to protect the passenger compartment and the occupants in the passenger compartment by deforming and transmitting the load to other members when the vehicle collides with an obstacle. .

The thickness of the rocker outer R/F is determined based on the size of the expected collision load. However, the wall thickness required for the rocker outer R/F (hereinafter referred to as the "necessary wall thickness") is not constant and differs depending on the location. For example, in general, the load applied during a frontal collision is assumed to be greater than the load applied during a side collision or a rear collision. Larger than the required wall thickness.

JP 2015-58749 A

In such a case, if the thickness of the rocker outer R/F is constant, the thickness of the rocker outer R/F is, of course, equal to or larger than the largest required thickness, that is, in the above example, the required thickness of the front portion. It should be thicker or more. In this case, the rear portion of the rocker outer R/F becomes thicker than necessary, which unnecessarily increases the weight of the vehicle.

Therefore, it is conceivable to form a tailored weld blank (hereinafter referred to as "TWB") by laser welding plate materials having different thicknesses, and to form the rocker outer R/F with this TWB. In this case, the thickness of the rocker outer R/F can be changed depending on the location, and the weight of the vehicle can be reduced.

Here, in TWB, two plate materials having different plate thicknesses are welded without overlapping in the thickness direction. Such welded portions are weaker in strength than other portions and are more likely to break than other portions. If an obstacle (for example, a utility pole or the like) hits the vicinity of the weld from the side, the weld may break. Therefore, conventionally, it has been difficult to configure the rocker outer with a TWB.

Patent Document 1 discloses a technique for reducing the moment load on the rocker outer R/F during a frontal collision by providing a weakened portion in the gusset that joins the rocker outer R/F and the front pillar. . However, in Patent Document 1, neither the use of TWB nor the side collision is considered.

Therefore, the present specification discloses a vehicle side structure that can appropriately protect the occupant in a side collision while reducing the weight of the vehicle.

The vehicle side structure disclosed in this specification includes a rocker outer R/F extending in the vehicle front-rear direction, and the rocker outer R/F includes a first member at least partially positioned below a front seat; A second member arranged behind one member and having a thickness different from that of the first member; a welded portion welded to a front end face of a second member, the welded portion being located below the front seat, and the rocker outer R/F having at least a portion forward of the welded portion and The seat cushion of the front seat is characterized in that a fragile portion whose strength is lower than that of the surrounding area is provided at a position behind a front end of the seat cushion of the front seat.

By welding the first member and the second member having different thicknesses, it is possible to reduce the weight of the vehicle. In addition, by providing a weakened portion in the rocker outer R/F at a position forward of the welded portion and rearward of the front end of the seat cushion of the front seat, if the pole collides from the side of the occupant seated in the front seat. At , the pole will collide in the vicinity of the weak point. As a result, stress concentrates around the fragile portion, and the stress concentration on the welded portion is alleviated. As a result, breakage at the welded portion is suppressed, and the occupant is appropriately protected. That is, according to the above configuration, it is possible to appropriately protect the occupant while reducing the weight of the vehicle.

In this case, the thickness of the first member may be greater than the thickness of the second member.

In general, the load during a frontal collision tends to be greater than the load during a rearward collision, so the front portion of the rocker outer R/F is required to have higher strength than the rear portion. With the above configuration, the front portion of the rocker outer R/F can be sufficiently strong, while the thickness of the rear portion can be kept small, thus making it possible to reduce the weight of the rocker outer R/F.

The rocker outer R/F includes side walls substantially parallel to the vehicle longitudinal direction and the vehicle vertical direction, a ceiling wall extending inward in the vehicle width direction from the upper end of the side wall, and a bottom extending inward in the vehicle width direction from the lower end of the side wall. and a wall, and the weakened portion may be provided on the top wall and the bottom wall.

By providing the fragile portion on both the top wall and the bottom wall, bending at the fragile portion occurs more reliably, and the bending can efficiently absorb the collision energy. And thereby, the fracture|rupture in a welded part can be prevented more reliably.

Further, the welded portion may be positioned below the seat back of the front seat.

With such a configuration, the welded portion is positioned slightly behind the chest of the occupant. Therefore, when the pole collides directly beside the chest of the occupant, the welded portion is positioned slightly behind the pole, which suppresses the impact load from being applied directly to the welded portion, thereby making the welded portion more likely to break. It can definitely be prevented.

Further, the welded portion may be positioned below a center pillar arranged between the front seat and the rear seat.

With such a configuration, when the pole collides with the welded portion, the pole also collides with the center pillar. In this case, since the collision load is also absorbed by the center pillar, stress concentration at the welded portion is alleviated, and breakage of the welded portion can be more reliably prevented.

According to the vehicle side structure disclosed in this specification, it is possible to appropriately protect the occupant in a side collision while reducing the weight of the vehicle.

FIG. 4 is a schematic view of the vehicle as seen from the side, showing the positions of lockers; It is a schematic longitudinal cross-sectional view of a locker. It is a schematic diagram of TWB. It is a partial perspective view of rocker outer R/F. It is a figure which shows the positional relationship of rocker outer R/F, a passenger|crew, and a pole. FIG. 4 is a stress distribution diagram of a rocker outer R/F having no weakened portion at the time of a side collision with a pole; FIG. 10 is a stress distribution diagram of a rocker outer R/F having a weakened portion at the time of a side collision with a pole;

The vehicle side structure will be described below with reference to the drawings. FIG. 1 is a schematic view of the vehicle viewed from the side, showing the position of the locker 10. FIG. In the drawings below, "Fr", "Up", and "Lh" indicate the front of the vehicle, the upper side of the vehicle, and the left side of the vehicle, respectively.

A front seat 22 on which an occupant 100 sits is provided in the front part of the passenger compartment. The front seat 22 has a seat cushion 26 supporting the buttocks of the occupant 100 and a seat back 24 standing from the rear end of the seat cushion 26 and supporting the back of the occupant 100 . A floor panel (not shown) is provided on the floor of the passenger compartment. The rockers 10 are arranged on both sides of the floor panel in the vehicle width direction. Rocker 10 is a frame member extending in the vehicle front-rear direction. The rocker 10 is constructed by combining a rocker outer R/F 12 and a rocker inner panel 14 (not visible in FIG. 1, see FIG. 2), which will be described later.

A front door opening 16 and a rear door opening 18 that serve as entrances for passengers 100 are formed in side portions of the vehicle. Each door opening 16, 18 is covered with a door (not shown) so that it can be opened and closed. A center pillar 20 extending in the vertical direction of the vehicle is provided between the front door opening 16 and the rear door opening 18 . A lower end of the center pillar 20 is connected to the rocker 10 . Further, in this example, the center pillar 20 is provided at a position overlapping the seat back 24 of the front seat 22 in a side view.

FIG. 2 is a schematic longitudinal sectional view of locker 10. As shown in FIG. As shown in FIG. 2 , the rocker 10 has a rocker outer R/F 12 and a rocker inner panel 14 . As shown in FIG. 2, the rocker outer R/F 12 includes a side wall 34 that stands upright in the vehicle vertical direction and extends in the vehicle front-rear direction, a ceiling wall 36 that extends substantially inward in the vehicle width direction from the upper end of the side wall 34, and a side wall It has a bottom wall 38 extending substantially inward in the vehicle width direction from the lower end of 34 and a flange 40 extending vertically from the top wall 36 and the bottom wall 38 . In other words, the rocker outer R/F 12 has a substantially hat-shaped cross section. The rocker inner panel 14 has a substantially hat-shaped cross section like the rocker outer R/F 12, and the upper and lower ends of the rocker inner panel 14 are joined to the flange 40 of the rocker outer R/F 12. As a result, the rocker outer R/F 12 and the rocker inner panel 14 form a closed cross section.

Note that the configuration of the locker 10 described here is merely an example, and the shape and components thereof may be changed as appropriate. For example, in this example, the rocker inner panel 14 has a hat-shaped cross section, but the rocker inner panel 14 may have a flat plate shape. Further, another member may be joined to the rocker inner panel 14 and the rocker outer R/F 12 to reinforce them.

Here, the rocker outer R/F 12 of this example is composed of a tailored welded blank (TWB). A TWB is made by welding plate materials with different thicknesses before press forming into a single blank. FIG. 3 is a schematic diagram of the TWB 50. As shown in FIG. In FIG. 3, the black hatched portion is the welded portion 54 where the two plate members 52a and 52b are welded. As shown in FIG. 3, in the TWB 50, the end surfaces of two plate members 52a and 52b are joined together by welding (for example, arc welding, laser welding, or the like). In other words, the two plate members 52a and 52b are joined without overlapping in the thickness direction. The rocker outer R/F 12 is constructed by press-molding such a TWB 50 .

FIG. 4 is a partial perspective view of the rocker outer R/F 12. FIG. As shown in FIGS. 1 and 4, the rocker outer R/F 12 of this example has a first member 28, a second member 30, and a welded portion 32 where the first member 28 and the second member 30 are welded together. The first member 28 has a first thickness t1, and at least a portion of the first member 28 is positioned below the front seat 22 as shown in FIG. In other words, the longitudinal range of the first member 28 overlaps the longitudinal range of the occupant 100 seated on the front seat 22 .

The second member 30 is arranged behind the first member 28 and has a second thickness t2 that is smaller than the first thickness t1. A welded portion 32 is a portion where the first member 28 and the second member 30 are welded together, and is a black hatched portion in FIGS. 1 and 4 . At this welded portion 32, the thickness changes abruptly from t1 to t2. In this example, the welding portion 32 is positioned below the seat back 24 and below the center pillar 20 . From another point of view, the welded portion 32 is positioned slightly behind the chest of the occupant 100 seated on the front seat 22 .

Here, the reason why the plate thickness of the rocker outer R/F 12 is changed with the welded portion 32 as a boundary will be described. When the vehicle collides with an obstacle, the rocker outer R/F 12 deforms and transmits the collision load to other members, thereby absorbing the collision load and protecting the passenger compartment as well as the occupants. In order to properly protect the occupant 100, the rocker outer R/F 12 is required to have sufficient strength. .

Specifically, in general, the load applied during a frontal collision tends to be larger than the load applied during a rearward collision or a side collision. Therefore, in general, the required strength of the front portion of the rocker outer R/F 12 tends to be greater than the required strength of the rear portion. In this way, if the thickness of the rocker outer R/F 12 is made uniform despite the fact that the required strength differs from place to place, the thickness of the rear portion becomes larger than necessary, and the weight of the rocker outer R/F 12 and thus the vehicle is increased. increases. Therefore, it is conceivable to reinforce only the front portion of the rocker outer R/F 12 with a reinforcing member while keeping the thickness of the entire rocker outer R/F 12 small. However, in this case, it is necessary to separately prepare a reinforcing member in addition to the rocker outer R/F 12, resulting in an increase in the number of parts.

In this example, as described above, in order to ensure the strength of the rocker outer R/F 12 while preventing an increase in weight and an increase in the number of parts, the thick first member 28, the thin second member 30, A rocker outer R/F 12 is composed of a TWB that is joined with . This makes it possible to secure appropriate strength for each of the front and rear portions of the rocker outer R/F 12 while suppressing an increase in weight and the number of parts.

However, when the rocker outer R/F 12 is made of TWB, the strength of the welded portion 32 becomes a problem. That is, the welded portion 32 is formed by locally applying heat and melting two plate materials by arc welding or laser welding to join them. Due to the heat input during welding, a softened portion due to welding, a so-called HAZ softened portion, is likely to occur around the welded portion 32 . In particular, the rocker outer R/F 12 is often made of high-strength steel or ultra-high-strength steel. In such high-strength steel materials or ultra-high-strength steel materials, martensite and bainite in the steel sheet are likely to be tempered by the heat effect of welding, and the hardness tends to decrease, resulting in marked HAZ softening.

If such a HAZ softened portion exists, the rocker 10 may be unintentionally broken in the event of a side collision with the pole. A pole side collision is a type of collision in which a pole-shaped obstacle such as a utility pole collides with the side of the vehicle, particularly directly to the side of the occupant 100 seated on the front seat 22 . It should be noted that the pole may collide not only directly beside the occupant 100, but also at a position in front of or behind the occupant 100. In this case, the impact on the occupant 100 is small. Thus, a case where the pole 110 collides with the occupant 100, particularly the chest of the occupant 100 will be described.

As described above, the position of the welded portion 32 in the front-rear direction is slightly behind the chest of the occupant 100 . Therefore, as shown in FIG. 5 , when pole 110 collides with the chest of occupant 100 , pole 110 is positioned slightly forward of welded portion 32 . In other words, in this case, the collision load due to the side collision with the pole is applied to the rocker outer R/F 12 in the vicinity of the welded portion 32 .

When a collision load is applied from the side, the rocker outer R/F 12 deforms greatly to absorb the collision load. However, if the HAZ softened portion exists in the welded portion 32, there is a risk that stress will concentrate on the welded portion 32 at the time of the pole side collision, and the welded portion 32 will break.

In this example, in order to alleviate the stress concentration on the welded portion 32 , the rocker outer R/F 12 is provided with a weakened portion 42 behind the front end of the seat cushion 26 and forwardly of the welded portion 32 . This will be described with reference to FIGS. 1 and 5. FIG. 1 and 5, La indicates the longitudinal position of the fragile portion 42 (not visible in FIGS. 1 and 5).

As shown in FIG. 5 and as described above, the weakened portion 42 is provided forward of the welded portion 32 . Therefore, the fragile portion 42 is provided in the first member 28 arranged forward of the welded portion 32 . Further, in this example, as shown in FIG. 4 , the through hole is the weakened portion 42, and the weakened portion 42 (through hole) is provided in each of the top wall 36 and the bottom wall 38 of the first member 28. there is By providing the fragile portion 42 on both the top wall 36 and the bottom wall 38 in this manner, the rocker outer R/F 12 is likely to bend near the fragile portion 42 .

As shown in FIG. 1 and as described above, the fragile portion 42 is positioned rearward of the front end of the seat cushion 26 . Such arrangement prevents the fragile portion 42 from being excessively separated from the pole 110 that collides with the occupant 100, so stress tends to concentrate on the fragile portion 42 in the event of a pole side collision. In this example, in particular, in order to bring the positions of the pole 110, which collides with the chest of the occupant 100, closer to the fragile portion 42, the fragile portion 42 is positioned within 300 mm in front of the welded portion 32, more preferably within the welded portion 32. It is located within 150mm in front of the Note that 300 mm and 150 mm are diameters and radii of common utility poles.

With the configuration as described above, when the pole 110 collides with the occupant 100 , particularly the chest of the occupant 100 , the stress tends to concentrate on the fragile portion 42 instead of the welded portion 32 . As a result, the rocker outer R/F 12 is largely deformed at the fragile portion 42 . Since the collision load is absorbed by the deformation of the fragile portion 42, the passenger compartment space and thus the occupant 100 are appropriately protected, stress concentration on the welded portion 32 is alleviated, and breakage at the welded portion 32 is effective. suppressed by

Next, the effect of this fragile portion 42 will be described with reference to FIGS. 6 and 7. FIG. FIG. 6 is a diagram showing the stress distribution of the rocker outer R/F 12 at the time of a pole side collision without the fragile portion 42. As shown in FIG. FIG. 7 is a diagram showing the stress distribution of the rocker outer R/F 12 at the time of a pole side collision when the fragile portion 42 is provided. In FIGS. 6 and 7, the greater the stress, the darker the density of the black hatching.

6 and 7, when the weakened portion 42 is provided (in the case of FIG. 7), the rocker outer R/F 12 is steeper than when the weakened portion 42 is not provided (in the case of FIG. 6). , and stress tends to concentrate near the bent portion. On the other hand, when the fragile portion 42 is provided (in the case of FIG. 7), stress concentration near the welded portion 32 is alleviated compared to when the fragile portion 42 is not provided (in the case of FIG. 6). I understand. As a result, when the fragile portion 42 is provided as in this example, breakage at the welded portion 32 can be effectively prevented, and the occupant 100 can be protected more appropriately.

As is clear from the above description, according to the vehicle side structure disclosed in this specification, the TWB can be applied to the rocker outer R/F 12, so that the weight of the vehicle can be reduced. Further, by providing the fragile portion 42 in the rocker outer R/F 12, it is possible to control the behavior of the rocker outer R/F 12 in the event of a side collision with the pole, and to appropriately protect the occupant 100. That is, according to the vehicle side structure disclosed in this specification, the weight of the vehicle can be reduced, and the vehicle occupant 100 can be appropriately protected in the event of a side collision.

The configuration described so far is only an example. As long as the fragile portion 42 is provided at a position forward of the seat cushion 32 and rearward of the front end of the seat cushion 26, other configurations may be changed as appropriate. For example, in the description so far, the through holes formed in the top wall 36 and the bottom wall 38 are the fragile portions 42. It can be in any form. For example, the fragile portion 42 may be a thin portion, a bent portion, a bead shape, a seat shape, or the like. Further, if the fragile portion 42 is positioned forward of the welded portion 32 and rearward of the front end of the seat cushion 26, the arrangement position and the number thereof may be changed. Accordingly, weakened portions 42 may be formed in sidewalls 34 and flanges 40 instead of or in addition to top wall 36 and bottom wall 38 . Also, in the description so far, the case where the thickness t1 of the first member 28 is greater than the thickness t2 of the second member 30 has been described. It may be larger than the thickness t1. Also, the fragile portion 42 may be additionally provided behind the welded portion 32 .

10 rocker, 12 rocker outer R/F, 14 rocker inner panel, 16 front door opening, 18 rear door opening, 20 center pillar, 22 front seat, 24 seat back, 26 seat cushion, 28 first member, 30 second member , 32 weld, 34 side wall, 36 top wall, 38 bottom wall, 40 flange, 42 weak point, 50 TWB, 100 occupant, 110 pole.

Claims (1)

Equipped with a rocker outer reinforcement extending in the longitudinal direction of the vehicle,
The rocker outer reinforcement is
a first member at least partially positioned below the front seat;
a second member disposed behind the first member and having a thickness different from that of the first member;
A welded portion in which the rear end surface of the first member and the front end surface of the second member are welded together without overlapping the first member and the second member in the thickness direction , the welded portion being located below the front seat. a weld located at
The rocker outer reinforcement has a weakened portion having a lower strength than its surroundings, at least at a position forward of the welded portion and rearward of the front end of the seat cushion of the front seat. ,
A vehicle side structure characterized by:

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