JP2021109501A - Vehicle side structure - Google Patents

Abstract

To provide a vehicle side structure capable of properly protecting an occupant in a case of a side impact while contributing to realization of a light-weight vehicle.SOLUTION: A vehicle side structure includes a locker outer reinforcement 12 extending in a vehicular fore-and-aft direction. The locker outer reinforcement 12 includes a first member 28 at least part of which is located below a front seat 22, a second member 30 which is disposed behind the first member 28 and has a different thickness from the first member 28, and a weld part 32 where a rear end of the first member 28 and a front end of the second member 30 are welded and which is located below the front seat 22. The locker outer reinforcement 12 has a fragile part 42, the strength of which is lower than that of the surroundings, located ahead the weld part 32 and behind the front end of a seat cushion 26 of the front seat 22.SELECTED DRAWING: Figure 4

Description

This specification discloses a vehicle side structure provided with a rocker outer lean force extending in the vehicle front-rear direction.

Generally, a rocker outer lean force (hereinafter referred to as "rocker outer R / F") extending in the front-rear direction of the vehicle is 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, by extension, the occupants in the passenger compartment by deforming or transmitting the load to other members when the vehicle collides with an obstacle. ..

The wall thickness of such a rocker outer R / F is determined based on the magnitude of the assumed collision load. However, the wall thickness required for the Rocker Outer R / F (hereinafter referred to as "required wall thickness") is not constant and varies depending on the location. For example, since it is generally assumed that the load applied during a frontal collision is larger than the load applied during a side collision and a rear collision, the required wall thickness of the front portion of the rocker outer R / F is the thickness of the rear portion. It will be larger than the required wall thickness.

Japanese Unexamined Patent Publication No. 2015-58749

In such a case, when the wall thickness of the rocker outer R / F is kept constant, the wall thickness of the rocker outer R / F is, of course, equal to or larger than the largest required wall thickness, that is, in the above example, the required meat of the front side portion. Must be thicker or thicker. In this case, the thickness of the rear portion of the rocker outer R / F becomes larger than necessary, so that the weight of the vehicle increases unnecessarily.

Therefore, it is also conceivable to laser-weld plate materials having different plate thicknesses to form a tailored weld blank (hereinafter referred to as "TWB"), and to form a rocker outer R / F with this TWB. In this case, the wall 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 a welded portion has a weaker strength than other portions and is more likely to break than other portions. When an obstacle (for example, a utility pole or the like) collides with the vicinity of the welded portion from the side, the welded portion may be broken. Therefore, conventionally, it has been difficult to configure the rocker outer with TWB.

Patent Document 1 discloses a technique for reducing the moment load on the rocker outer R / F at the time of a frontal collision by providing a fragile 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 described above nor the side collision is considered.

Therefore, the present specification discloses a vehicle side structure capable of appropriately protecting an occupant in the event of a side collision while reducing the weight of the vehicle.

The vehicle side structure disclosed in the present specification includes a rocker outer R / F extending in the front-rear direction of the vehicle, and the rocker outer R / F includes a first member whose at least a part is located below the front seat and the first member. A welded portion in which a second member arranged behind one member and having a thickness different from that of the first member, and a rear end of the first member and a front end of the second member are welded to each other, and the front seat. It has a welded portion located below the seat, and is stronger than the surroundings at least at a position of the rocker outer R / F that is in front of the welded portion and behind the front end of the seat cushion of the front seat. It is characterized in that a reduced vulnerable part is provided.

By welding the first member and the second member having different thicknesses, the weight of the vehicle can be reduced. In addition, when the pole collides from the side of the occupant seated in the front seat by providing a fragile portion in the rocker outer R / F at a position in front of the welded portion and behind the front end of the seat cushion of the front seat. In, the pole will collide in the vicinity of the vulnerable part. As a result, the stress is concentrated around the fragile portion, and the stress concentration on the welded portion is relaxed. As a result, breakage at the weld is suppressed and the occupant is adequately protected. That is, according to the above configuration, it is possible to appropriately protect the occupants while reducing the weight of the vehicle.

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

In general, the load at the time of a frontal collision tends to be larger than the load at the time of a rear surface collision, so that the front side portion of the rocker outer R / F is required to have higher strength than the rear side portion. With the above configuration, it is possible to reduce the weight of the rocker outer R / F because the wall thickness of the rear portion can be kept small while ensuring sufficient strength for the front portion.

The rocker outer R / F has a side wall substantially parallel to the vehicle front-rear direction and the vehicle vertical direction, a top 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. The fragile portion may be provided on the top wall and the bottom wall, including a wall.

By providing the fragile portion on both the top wall and the bottom wall, bending in the fragile portion is more reliably generated, and the collision energy can be efficiently absorbed by the bending. As a result, breakage at the welded portion can be prevented more reliably.

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

With such a configuration, the weld is located slightly behind the occupant's chest. Therefore, when the pole collides with the occupant's chest right beside, the weld is located slightly behind the pole, suppressing the collision load from being applied directly to the weld and causing the weld to break more. It can be reliably prevented.

Further, the welded portion may be located below the 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, the stress concentration in the welded portion is relaxed, and the fracture of the welded portion can be prevented more reliably.

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

It is a schematic view which looked at the vehicle from the side, and is the figure which shows the position of a rocker. It is a schematic vertical sectional view of a rocker. It is a schematic diagram of TWB. It is a partial perspective view of the rocker outer R / F. It is a figure which shows the positional relationship between a rocker outer R / F, an occupant, and a pole. It is a stress distribution map at the time of a pole side collision of a rocker outer R / F having no fragile part. It is a stress distribution map at the time of a pole side collision of a rocker outer R / F having a fragile part.

Hereinafter, the vehicle side structure will be described with reference to the drawings. FIG. 1 is a schematic view of the vehicle viewed from the side, and is a diagram showing the position of the rocker 10. 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 the occupant 100 is seated is provided at the front of the passenger compartment. The front seat 22 has a seat cushion 26 that supports the buttocks of the occupant 100, and a seat back 24 that stands from the rear end of the seat cushion 26 and supports the back of the occupant 100. Floor panels (not shown) are 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. The rocker 10 is a skeleton member extending in the front-rear direction of the vehicle. The rocker 10 is configured by combining the rocker outer R / F12 and the 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 which serve as entrances and exits for the occupant 100 are formed on the side portion of the vehicle. The door openings 16 and 18 are covered by a door (not shown) so as to be openable and closable. Further, 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. The 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 where it overlaps with the seat back 24 of the front seat 22 in the side view.

FIG. 2 is a schematic vertical sectional view of the rocker 10. As shown in FIG. 2, the rocker 10 has a rocker outer R / F12 and a rocker inner panel 14. As shown in FIG. 2, the rocker outer R / F12 has a side wall 34 that is erected in the vertical direction of the vehicle and extends in the front-rear direction of the vehicle, a top 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 inward in the width direction of the vehicle from the lower end of the 34, and a flange 40 extending in the vertical direction from the top wall 36 and the bottom wall 38. In other words, the Rocker Outer R / F12 has a substantially hat-shaped cross section. The rocker inner panel 14 has a substantially hat-shaped cross section like the rocker outer R / F12, and the upper and lower ends of the rocker inner panel 14 are joined to the flange 40 of the rocker outer R / F12. As a result, a closed cross section is formed between the rocker outer R / F12 and the rocker inner panel 14.

The configuration of the rocker 10 described here is an example, and its shape and components may be changed as appropriate. For example, in this example, the rocker inner panel 14 has a hat shape in cross section, but the rocker inner panel 14 may have a flat plate shape. Further, another member for reinforcing the rocker inner panel 14 and the rocker outer R / F12 may be further joined.

Here, the rocker outer R / F12 of this example is composed of a tailor welded blank (TWB). In TWB, plate materials having different plate thicknesses are welded before press molding to form a single blank. FIG. 3 is a schematic view of the TWB 50. In FIG. 3, the black hatched portion is a welded portion 54 obtained by welding two plate members 52a and 52b. As shown in FIG. 3, in TWB50, the end faces of the two plate members 52a and 52b are joined by welding (for example, arc welding, laser welding, etc.). In other words, the two plate members 52a and 52b are joined without overlapping in the thickness direction. The rocker outer R / F12 is formed by press-molding such a TWB50.

FIG. 4 is a partial perspective view of the Rocker Outer R / F12. As shown in FIGS. 1 and 4, the rocker outer R / F12 of this example has a first member 28, a second member 30, and a welded portion 32 obtained by welding the first member 28 and the second member 30. The first member 28 has a first wall thickness t1 and, as shown in FIG. 1, at least a part thereof is located below the front seat 22. In other words, the front-rear direction range of the first member 28 overlaps with the front-rear direction 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 wall thickness t2 that is smaller than the first wall thickness t1. The welded portion 32 is a portion where the first member 28 and the second member 30 are welded, and is a black hatched portion in FIGS. 1 and 4. In this welded portion 32, the wall thickness suddenly changes from t1 to t2. Further, in this example, it is located below the seat back 24 of the welded portion 32 and below the center pillar 20. From another point of view, the welded portion 32 is located slightly behind the chest of the occupant 100 seated on the front seat 22.

Here, the reason for changing the plate thickness of the rocker outer R / F12 with the welded portion 32 as a boundary will be described. When the vehicle collides with an obstacle, the rocker outer R / F12 deforms or transmits the collision load to other members to absorb the collision load and protect the passenger compartment and the occupants. The rocker outer R / F12 is required to have sufficient strength in order to appropriately protect the occupant 100, but the strength required for the rocker outer R / F12 (hereinafter referred to as "required strength") varies depending on the location. ..

Specifically, in general, the load applied at the time of a frontal collision tends to be larger than the load applied at the time of a rear surface collision and a side collision. Therefore, in general, the required strength of the front side portion of the rocker outer R / F12 tends to be larger than the required strength of the rear side portion. In this way, if the wall thickness of the rocker outer R / F12 is made uniform even though the required strength differs depending on the location, the wall thickness of the rear part becomes larger than necessary, and the rocker outer R / F12 and thus the weight of the vehicle. Will increase. Therefore, while keeping the wall thickness of the entire rocker outer R / F12 small, it is conceivable to reinforce only the front side portion of the rocker outer R / F12 with a reinforcing member. However, in this case, it is necessary to separately prepare a reinforcing member in addition to the rocker outer R / F12, which causes an increase in the number of parts.

In this example, in order to secure the strength of the rocker outer R / F12 while preventing the increase in weight and the number of parts, as described above, the thick first member 28 and the thin second member 30 are used. The rocker outer R / F12 is composed of the TWB joined together. As a result, it is possible to secure appropriate strength for each of the front side portion and the rear side portion of the rocker outer R / F12 while suppressing an increase in weight and the number of parts.

However, when the rocker outer R / F12 is composed of TWB, the strength of the welded portion 32 becomes a problem. That is, the welded portion 32 is formed by locally heat-receiving and melting the two plate materials by arc welding or laser welding to bond them. Due to the heat input during welding, a softened portion due to welding, a so-called HAZ softened portion, is likely to be generated around the welded portion 32. In particular, the rocker outer R / F12 is often made of a high-strength steel material or an ultra-high-strength steel material. In such high-strength steel materials or ultra-high-strength steel materials, martensite and bainite in the steel sheet are easily tempered by the heat effect of welding, and the hardness tends to decrease, and HAZ softened portions are remarkably generated.

When such a HAZ softened zone is present, the rocker 10 may break unexpectedly at the time of a side collision of the pole. The pole side collision is a collision mode in which a pole-shaped obstacle such as a utility pole collides with the side surface of the vehicle, particularly right beside the occupant 100 seated on the front seat 22. The pole may collide with the occupant 100 in front of or behind the occupant 100, not just beside the occupant 100. However, in this case, the effect on the occupant 100 is small, so that the pole is shown in FIG. 5 in this specification. As described above, the 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 rearward of the chest of the occupant 100. Therefore, as shown in FIG. 5, when the pole 110 collides with the chest of the occupant 100, the pole 110 is located slightly in front of the welded portion 32. In other words, in this case, the collision load due to the pole side collision is applied to the vicinity of the welded portion 32 in the rocker outer R / F12.

When a collision load is applied from the side, the rocker outer R / F12 is greatly deformed to absorb the collision load. However, if the HAZ softened portion is present in the welded portion 32, stress is concentrated on the welded portion 32 at the time of a pole side collision, and there is a possibility that the welded portion 32 may be broken.

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

As shown in FIG. 5, and as described above, the fragile portion 42 is provided in front of the welded portion 32. Therefore, the fragile portion 42 is provided on the first member 28 arranged in front of the welded portion 32. Further, in this example, as shown in FIG. 4, the through hole is a fragile portion 42, and the fragile portion 42 (through hole) is provided on 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 way, the rocker outer R / F12 is likely to bend in the vicinity of the fragile portion 42.

Further, the fragile portion 42 is located behind the front end of the seat cushion 26 as shown in FIG. 1 and as described above. With such an arrangement, the fragile portion 42 does not excessively separate from the pole 110 that collides with the occupant 100, so that stress is likely to be concentrated on the fragile portion 42 at the time of a side collision of the pole. In this example, in order to bring the pole 110 that collides with the chest of the occupant 100 and the fragile portion 42 closer to each other, the fragile portion 42 is placed within 300 mm in front of the welded portion 32, more preferably the welded portion 32. It is arranged within a range of 150 mm in front of the vehicle. In addition, 300 mm and 150 mm are diameters and radii of general utility poles.

With the above configuration, when the pole 110 collides with the occupant 100, particularly the chest of the occupant 100, the stress is likely to be concentrated not on the welded portion 32 but on the fragile portion 42. As a result, the rocker outer R / F12 is greatly deformed in the fragile portion 42. Since the collision load is absorbed by the deformation of the fragile portion 42, the passenger compartment space and eventually the occupant 100 are appropriately protected, the stress concentration on the welded portion 32 is alleviated, and the fracture at the welded portion 32 is effective. Is suppressed.

Next, the effect of the vulnerable portion 42 will be described with reference to FIGS. 6 and 7. FIG. 6 is a diagram showing the stress distribution of the rocker outer R / F12 at the time of a pole side collision when there is no fragile portion 42. Further, FIG. 7 is a diagram showing the stress distribution of the rocker outer R / F12 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 higher the density of black hatching.

As is clear from the comparison between FIGS. 6 and 7, the rocker outer R / F12 is steeper when the fragile portion 42 is provided (in the case of FIG. 7) than when the fragile portion 42 is not provided (in the case of FIG. 6). It bends to the surface, and stress tends to concentrate near the bent part. On the other hand, when the fragile portion 42 is provided (in the case of FIG. 7), the stress concentration in the vicinity of the welded portion 32 is relaxed as compared with the case where 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 in 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 the present specification, since the TWB can be applied to the rocker outer R / F12, the weight of the vehicle can be reduced. Further, by providing the fragile portion 42 on the rocker outer R / F12, the behavior of the rocker outer R / F12 at the time of a pole side collision can be controlled, and the occupant 100 can be appropriately protected. That is, according to the vehicle side structure disclosed in the present specification, it is possible to appropriately protect the occupant 100 in the event of a side collision while reducing the weight of the vehicle and reducing the weight of the vehicle.

The configuration described so far is an example, in which the rocker outer R / F12 has a first member 28 and a second member 30 connected via a welded portion 32, and the welded portion of the rocker outer R / F12. If the fragile portion 42 is provided at a position in front of 32 and behind the front end of the seat cushion 26, other configurations may be appropriately changed. For example, in the explanation so far, the through holes formed in the top wall 36 and the bottom wall 38 are referred to as the fragile portion 42, but the fragile portion 42 is other if the strength is lower than the surroundings thereof. It may be in the form. For example, the fragile portion 42 may be a thin-walled portion, a bent portion, a bead shape, a seat shape, or the like. Further, as long as the fragile portion 42 is located in front of the welded portion 32 and behind the front end of the seat cushion 26, its arrangement position and number may be changed. Therefore, the fragile portion 42 may be formed on the side wall 34 or the flange 40 in place of or in addition to the top wall 36 and the bottom wall 38. Further, in the above description, the case where the wall thickness t1 of the first member 28 is larger than the wall thickness t2 of the second member 30 has been described, but the wall thickness t2 of the second member 30 is the wall thickness t2 of the first member 28. The wall thickness may be larger than t1. Further, 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 welds, 34 side walls, 36 top walls, 38 bottom walls, 40 flanges, 42 fragile parts, 50 TWB, 100 occupants, 110 poles.

Claims (1)

Equipped with a rocker outer force that extends in the front-rear direction of the vehicle
The Rocker Outer Lean Force
With the first member, which is at least partly located below the front seats,
A second member arranged behind the first member and having a thickness different from that of the first member,
A welded portion in which the rear end of the first member and the front end of the second member are welded, and a welded portion located below the front seat.
At least at a position in front of the welded portion and behind the front end of the seat cushion of the front seat, a fragile portion having a strength lower than that of the surroundings is provided in the rocker outer force. ,
The vehicle side structure is characterized by this.

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