Vehicle underbody structure

Abstract

The present invention provides a vehicle underbody structure that can reduce deformation of the floor panel by suppressing the transmission of the frontal impact load to the tunnel side member towards the rear during a vehicle frontal collision. [Solution] The vehicle is equipped with a bag-shaped torque box 13 that connects the front of the body frame and the front of the tunnel side member 141. The torque box 13 connects the dash panel 16 and the tunnel side member 141, whose ends are spaced apart in the front-rear direction. The torque box 13 has a bulge portion 131 that bulges outward in a bag shape at a location forward of the part to which the tunnel side member 141 is joined. The bulge portion 131 is provided so as to be the starting point of bending deformation in which the front part 13a is displaced upward together with the inclined portion 161 of the dash panel 16 when the vehicle is struck head-on.

Description

Technical Field

[0001] The present invention relates to an underbody structure of a vehicle.

Background Art

[0002] When a vehicle collides head-on, deformation of the floor panel may occur due to the rearward movement of the power source mounted on the front part of the vehicle. As a countermeasure against such a head-on load, a structure in which the skeletal members under the floor panel are connected by a torque box has been conventionally adopted.

[0003] Patent Document 1 discloses a structure in which the front part of a tunnel side member and the front part of a floor frame are connected by a torque box. Further, in the vehicle of Patent Document 1, the front part of the floor frame and the front part of the side sill are connected by another torque box.

[0004] By connecting the front parts of the skeletal members to each other with a torque box as described above, it becomes possible to disperse the head-on load to a plurality of skeletal members connected by the torque box.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] By the way, in battery electric vehicles and hybrid electric vehicles, research and development have been conducted to increase the strength of the front end of the tunnel side member in response to the increase in vehicle weight due to the mounting of electric drive components (electric drive components including a battery). <http: / / www.google.co.jp / patents / ...

[0007] However, if the front end of the tunnel side member is strengthened as described above, there is a concern that the frontal impact load will be transmitted to the rear of the torque box and tunnel side member, worsening the deformation of the floor panel. Since such deformation of the floor panel affects the occupant's ankle injury value, it is necessary to suppress the transmission of load to the rear of the tunnel side member during a vehicle frontal impact. It should be noted that suppressing the transmission of frontal impact load to the rear of the tunnel side member during a vehicle frontal impact is required not only for electric vehicles but also for engine-powered vehicles.

[0008] The present invention aims to solve the above-mentioned problems and provides a vehicle underbody structure that can reduce deformation of the floor panel by suppressing the transmission of the frontal impact load to the tunnel side member towards the rear during a vehicle frontal collision. [Means for solving the problem]

[0009] An underbody structure for a vehicle according to one aspect of the present invention comprises: a dash panel provided to separate the passenger compartment of the vehicle from the front of the vehicle ahead of the passenger compartment; a pair of front side frames provided on both sides in the vehicle width direction at the front of the vehicle, each extending in the vehicle longitudinal direction; a pair of body frames provided connected at their front ends to each of the pair of front side frames, each extending in the vehicle longitudinal direction; a tunnel provided in the central part in the vehicle width direction below the passenger compartment, extending in the vehicle longitudinal direction and having an upwardly bulging shape; a pair of tunnel side members provided along both sides in the vehicle width direction of the tunnel, extending in the vehicle longitudinal direction, each having its front end spaced rearward from the dash panel; and a connection provided to connect the front of each of the body frames to the front of each of the tunnel side members. Each includes a pair of torque boxes, each having a bag shape, and a floor panel provided behind the dash panel, extending in the vehicle width direction and the vehicle longitudinal direction so as to cover the pair of tunnel side members and the pair of torque boxes. The rear of the dash panel has an inclined portion that slopes downward from front to rear. Each of the torque boxes is joined to the rear of the dash panel at its front and has a bulge portion in the middle of the torque box in the vehicle longitudinal direction that bulges outward toward the bag shape. The bulge portion is provided so as to be the starting point of bending deformation in which the portion of the torque box in front of the bulge portion displaces upward toward the vehicle when a frontal impact load is applied to the torque box during a vehicle frontal collision, together with the inclined portion of the dash panel.

[0010] The underbody structure of the vehicle according to the above embodiment includes a torque box having a bulge. The bulge of the torque box is positioned so that when a frontal impact load is applied during a vehicle frontal collision, the portion of the torque box in front of the bulge, along with the inclined portion of the dash panel, becomes the starting point for upward bending deformation. Therefore, at least a portion of the applied frontal impact load is distributed to cause bending deformation of the portion of the torque box in front of the bulge and the inclined portion of the dash panel. Thus, the underbody structure of the vehicle according to the above embodiment suppresses the transmission of the frontal impact load to the tunnel side member in a rearward direction during a vehicle frontal impact, and can suppress deformation of the floor panel behind the bulge.

[0011] In the underbody structure of the vehicle according to the above embodiment, each of the torque boxes has a ridge extending in the longitudinal direction of the vehicle on its outer surface, and the bulging portion may be provided so as to cross the ridge.

[0012] In the underbody structure of the vehicle according to the above embodiment, the bulge is provided so as to cross the ridge line, making it easier to bend the portion in front of the bulge upward when a frontal load is applied, starting from the bulge. In other words, if the bulge were provided so as not to cross the ridge line, it is conceivable that bending deformation would be difficult to occur due to the rigidity of the ridge line even when a frontal load is applied. In contrast, by providing the bulge to cross the ridge line, bending deformation can be made easier to occur when a frontal load is applied.

[0013] In the underbody structure of the vehicle according to the above embodiment, the bulging portion may be provided at a location in the longitudinal direction of the vehicle that is spaced further forward than the front end of the tunnel side member.

[0014] In the underbody structure of the vehicle according to the above embodiment, the bulge is provided at a location spaced forward of the front end of the tunnel side member, thereby suppressing the inhibition of bending deformation due to forward loads by the tunnel side member. That is, if the bulge were provided at a location rearward of the front end of the tunnel side member, bending would be difficult due to the rigidity of the tunnel side member. In contrast, by providing the bulge at a location spaced forward of the front end of the tunnel side member, bending deformation is not inhibited by the rigidity of the tunnel side member, and the bulge reliably functions as the starting point for bending deformation.

[0015] In the underbody structure of the vehicle according to the above embodiment, each of the torque boxes has a front upper surface at the front portion to which the rear portion of the dash panel is joined, which is an upper surface composed of an inclined surface along the inclined portion of the dash panel, and the bulge portion may be provided at a location in the longitudinal direction of the vehicle where the lower end of the inclination of the front upper surface is located.

[0016] In the underbody structure of the vehicle according to the above embodiment, the front upper surface of the torque box is composed of an inclined surface, and a bulge is provided at the location where the lower end of the inclination of the front upper surface is located (where the upper surface bends). Therefore, when a frontal impact load is input to the torque box, the bulge reliably functions as the starting point for bending deformation. For this reason, in the event of a vehicle frontal impact, it is possible to easily bend the portion in front of the bulge, starting from the bulge.

[0017] In the underbody structure of the vehicle according to the above embodiment, the bulging portion may be positioned in the longitudinal direction of the vehicle at a location forward of the heel position of an occupant seated in the front seat in the passenger compartment.

[0018] Since the underbody structure of the vehicle according to the above aspect has a bulging portion disposed at a location in front of the heel position of the occupant sitting in the front seat, even when a frontal impact load is input, the bending deformation starting from the bulging portion suppresses the load transmission of the tunnel side member backward, and the deformation of the floor panel at the heel position can be reduced. Therefore, it is possible to suppress the deterioration of the occupant ankle injury value.

Advantages of the Invention

[0019] The underbody structure of the vehicle according to each of the above aspects can suppress the transmission of the frontal impact load backward to the tunnel side member and reduce the deformation of the floor panel when the vehicle undergoes a frontal collision.

Brief Description of the Drawings

[0020] [Figure 1] FIG. 15 is a bottom view of a part of the underbody structure of the vehicle according to the embodiment as viewed from below the vehicle. [Figure 2] FIG. 18 is a top view of a part of the underbody structure of the vehicle as viewed from above the vehicle. [Figure 3] FIG. 21 is an enlarged bottom view showing an enlarged view of the portion indicated by arrow A in FIG. 1. [Figure 4] FIG. 24 is a perspective view of the torque box as viewed obliquely from the lower side. [Figure 5] FIG. 27 is a perspective view for explaining the positional relationship of the bulging portion of the torque box in the vehicle front-rear direction. [Figure 6] FIG. 30 is a schematic diagram showing the behavior of the engine and transmission during an offset collision. [Figure 7] FIG. 33 is a perspective view showing the deformation mode of the torque box when a collision load is input from the front.

Modes for Carrying Out the Invention

[0021] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the embodiments described below are illustrative of the present invention, and the present invention is not limited to the following embodiments except for its essential configuration.

[0022] Furthermore, in the diagrams used in the following explanation, "FR" indicates the front of the vehicle, "RR" indicates the rear of the vehicle, "LH" indicates the left side of the vehicle, "RH" indicates the right side of the vehicle, "UP" indicates the top of the vehicle, and "LO" indicates the bottom of the vehicle. Additionally, "IN" indicates the inside in the vehicle width direction, and "OUT" indicates the outside in the vehicle width direction.

[0023] 1. Underbody structure of vehicle 1 The underbody structure of vehicle 1 according to this embodiment will be described with reference to Figures 1 and 2. Figure 1 is a bottom view of a part of the underbody structure of vehicle 1 as seen from the underside of the vehicle, and Figure 2 is a top view of a part of the underbody structure of vehicle 1 as seen from the topside of the vehicle.

[0024] As shown in Figure 2, the vehicle 1 includes a dash panel 16 that separates the passenger compartment 1a from the front of the vehicle (for example, the powertrain room) 1b located in front of the passenger compartment 1a.

[0025] Furthermore, as shown in Figures 1 and 2, the vehicle 1 comprises a pair of front side frames 11, a pair of body frames 12, and a pair of floor frames 17. The pair of front side frames 11 are arranged on both sides in the width direction of the front part 1b of the vehicle, and each is provided to extend in the longitudinal direction of the vehicle. The pair of body frames 12 are connected to each of the pair of front side frames 11 at their front ends, and each is provided to extend in the longitudinal direction of the vehicle below the passenger compartment 1a. Each of the pair of floor frames 17 is arranged on top of each of the pair of body frames 12 and is provided to extend in the longitudinal direction of the vehicle.

[0026] Furthermore, the vehicle 1 comprises a tunnel 14, a pair of tunnel side members 141, a pair of torque boxes 13, a floor panel 18, and a pair of cross members 19, all located below the passenger compartment 1a. The tunnel 14 is provided below the passenger compartment 1a, with its central portion in the vehicle width direction extending in the vehicle longitudinal direction, and has a shape that bulges upward (towards the passenger compartment). Each of the pair of tunnel side members 141 is provided to extend in the vehicle longitudinal direction along both sides of the tunnel 14 in the vehicle width direction. Each tunnel side member 141 has a U-shaped cross-section that opens upward (towards the foreground of the paper in Figure 2) and recesses downward (towards the foreground of the paper in Figure 1).

[0027] Each of the pair of torque boxes 13 is provided to connect the front ends of the body frame 12 and the front ends of the tunnel side members 141, and each has a bag shape (box shape). The floor panel 18 is joined to the dash panel 16 at its front end and is provided below the passenger compartment 1a so as to extend in the vehicle width direction and the vehicle longitudinal direction. In the vehicle 1 according to this embodiment, the floor panel 18 has a configuration that divides into left and right sides in the vehicle width direction, with the tunnel 14 as the boundary.

[0028] Each of the pair of cross members 19 is provided to extend outward in the vehicle width direction, with the tunnel 14 as the boundary. Each cross member 19 is joined to the side sill 15 on the outside in the vehicle width direction. Although Figure 2 only shows the pair of cross members 19 located at the very front in the vehicle's longitudinal direction, in vehicle 1, multiple pairs of cross members 19 are provided spaced apart from each other in the vehicle's longitudinal direction.

[0029] 2. Structure of Torque Box 13 The structure of the torque box 13 will be explained using Figures 3 and 4.

[0030] As shown in Figures 3 and 4, the torque box 13 is joined to the rear of the dash panel 16 (including the inclined portion 161) at the front portion 13a, which is the front part in the longitudinal direction of the vehicle, and to the tunnel side member 141 at the rear portion 13b.

[0031] The torque box 13 extends in the vehicle width direction inward and in the vehicle longitudinal direction, and is formed to extend outward from its front end in the vehicle width direction, and has a portion 13e that protrudes downward (hereinafter referred to as the "downward protrusion"). The front end of the tunnel side member 141 is inserted into the portion 13f that is onward in the vehicle width direction within the downward protrusion 13e (hereinafter referred to as the "inner protrusion") and joined at the insertion portion.

[0032] The inner protrusion 13f has two ridges 132 and 133 on its outer surface, each extending in the longitudinal direction of the vehicle. One of the two ridges 132, 133, is located above the other ridge 133.

[0033] The torque box 13 has a bulge 131 on its inner protruding portion 13f. The bulge 131 is located in the middle of the torque box 13 in the vehicle's longitudinal direction and is shaped to bulge inward in the vehicle's width direction (outward towards the bag shape). The bulge 131 is shaped to cross the ridge 132 located above it.

[0034] In this embodiment, the bulge 131 is configured to cross only one ridge 132, but it is also possible to configure the bulge 131 to cross both ridges 132 and 133.

[0035] 3. Formation location of the bulge 131 in the torque box 13 The formation location of the bulge 131 in the torque box 13 will be explained with reference to Figure 5.

[0036] As shown in Figure 5, the dash panel 16 has an inclined portion 161 at the rear, which is the rear part in the longitudinal direction of the vehicle, that slopes downward as it goes from the front to the rear.

[0037] The torque box 13 has a front upper surface 13c in its front portion 13a, to which the rear portion of the dash panel 16 is joined, which is formed by an inclined surface that follows the inclined portion 161 of the dash panel 16. The torque box 13 has a rear upper surface 13d in the portion behind the front upper surface 13c which is formed by a substantially horizontal surface. In the torque box 13, the bulge 131 is provided at the boundary between the front upper surface 13c and the rear upper surface 13d in the longitudinal direction of the vehicle, in other words, at the location where the lower end of the inclination of the front upper surface 13c is located.

[0038] The front end 141a of the tunnel side member 141 is positioned rearward and spaced apart from the rear end 16a of the dash panel 16 in the longitudinal direction of the vehicle. The bulge 131 of the torque box 13 is located forward and spaced apart from the front end 141a of the tunnel side member 141 in the longitudinal direction of the vehicle.

[0039] In the longitudinal direction of the vehicle, the heel position of an occupant seated in the front seat of the passenger compartment 1a is at the position indicated by symbol B and its vicinity. The bulge 131 of the torque box 13 is located at a position forward and separated from the occupant's heel position (the position indicated by symbol B and its vicinity).

[0040] 4. Deformation of the torque box 13 during a vehicle frontal collision. The deformation of the torque box 13 during a vehicle frontal collision will be explained using Figures 6 and 7.

[0041] As shown in Figure 6, we assume that vehicle 1 is moving forward (arrow C1) and is colliding head-on with a barrier (e.g., a honeycomb barrier) 500 in front of it (offset collision). The barrier 500 is positioned offset to the left with respect to the center CL1 in the vehicle width direction of vehicle 1. As an example, the barrier 500 is positioned so that 40% of vehicle 1 overlaps with it.

[0042] In this embodiment, the vehicle 1 is equipped with an engine 20 and a transmission 21 as a powertrain in the front part 1b of the vehicle. However, the powertrain may be an electric motor. In the event of a frontal collision, the engine 20 and transmission 21 can be considered as rigid bodies and are thought to deform very little. Therefore, as shown in Figure 6, in the event of a frontal collision, as indicated by arrow C2, a load acts on the dash panel 16, causing the engine 20 and transmission 21 to rotate counterclockwise in a top view from above, pushing it backward.

[0043] As shown in Figure 7, when such a forward load is applied, the portion of the torque box 13's front part 13a that is forward of the bulge 131 bends upward, starting from the bulge 131, together with the inclined portion 161 of the dash panel 16 (arrow D). In this case, in the longitudinal direction of the vehicle, the bulge 131 is forward of the tunnel side member 141 and is relative to the occupant's heel position AR. F Since it is located further forward than the position indicated by symbol B in Figure 7 and its surrounding area, bending deformation can reduce the rearward load transmission to the tunnel side member 141 and the impact on the occupant's heel.

[0044] 5. Effects The underbody structure of the vehicle 1 according to this embodiment includes a torque box 13 having a bulge 131. The bulge 131 of the torque box 13 is positioned so that when a frontal impact load is applied during a vehicle frontal collision, the portion of the torque box 13 in front of the bulge 131, together with the inclined portion 161 of the dash panel 16, becomes the starting point for upward bending deformation. Therefore, at least a portion of the applied frontal impact load is distributed to cause bending deformation of the portion of the torque box 13 in front of the bulge 131 and the inclined portion 161 of the dash panel 16. Thus, even during a vehicle frontal impact, the transmission of the frontal impact load to the tunnel side member 141 toward the rear is suppressed, and deformation of the floor panel 18 behind the bulge 131 is suppressed.

[0045] Furthermore, in the underbody structure of the vehicle 1 according to this embodiment, the bulge portion 131 is provided so as to cross the ridge line 132, making it easier to bend the portion in front of the bulge portion 131 upward when a forward load is applied. In other words, if the bulge portion were provided so as not to cross the ridge line 132, it is conceivable that bending deformation would be difficult to occur due to the rigidity of the ridge line 132 even when a forward load is applied. In contrast, by providing the bulge portion 131 so as to cross the ridge line 132, bending deformation can be easily generated when a forward load is applied.

[0046] Furthermore, in the underbody structure of the vehicle 1 according to this embodiment, the bulge 131 is provided at a location spaced forward of the front end 141a of the tunnel side member 141, thereby suppressing the inhibition of bending deformation due to forward loads by the tunnel side member 141. That is, if the bulge 131 were provided at a location rearward of the front end 141a of the tunnel side member 141, bending deformation would be difficult to occur due to the rigidity of the tunnel side member 141. In contrast, by providing the bulge 131 at a location spaced forward of the front end 141a of the tunnel side member 141, bending deformation is not inhibited by the rigidity of the tunnel side member 141, and the bulge 131 reliably functions as the starting point for bending deformation.

[0047] Furthermore, in the underbody structure of the vehicle 1 according to this embodiment, the front upper surface 13c of the torque box 13 is composed of an inclined surface, and the bulge 131 is provided at the location where the lower end of the inclination of the front upper surface 13c is located (where the upper surface bends). Therefore, when a frontal impact load is input to the torque box 13, the bulge 131 reliably functions as the starting point for bending deformation. For this reason, in the event of a vehicle frontal impact, it is possible to easily bend the portion in front of the bulge 131, starting from the bulge 131.

[0048] Furthermore, the underbody structure of the vehicle 1 according to this embodiment is such that the heel position of the occupant seated in the front seat (the position indicated by reference numeral B in Figure 5 and its surrounding area) AR FSince the bulge 131 is positioned further forward, even when a forward impact load is applied, bending deformation originating from the bulge 131 prevents the load from being transmitted to the tunnel side member 141 towards the rear, thus maintaining the heel position AR F This reduces deformation of the floor panel 18. Therefore, it is possible to suppress the worsening of occupant ankle injury values.

[0049] As described above, the underbody structure of the vehicle 1 according to this embodiment can reduce deformation of the floor panel 18 by suppressing the transmission of the frontal impact load to the tunnel side member 141 towards the rear during a frontal collision.

[0050] [Differentiation] In the above embodiment, the torque box 13 is provided with a bulge 131 that crosses the ridge line 132. However, in the present invention, it is not necessary to provide the bulge 131 so as to cross the ridge line 132. That is, even if the bulge does not necessarily cross the ridge line, it is sufficient if the bulge becomes the starting point of bending deformation when a forward load is applied.

[0051] Furthermore, in the above embodiment, the bulge 131 in the torque box 13 crosses only the ridge line 132, but in the present invention, the bulge 131 may cross the ridge line 133 in addition to the ridge line 132.

[0052] Furthermore, in the above embodiment, a bulge 131 is provided in the torque box 13 at the location where the lower end of the inclination on the front upper surface 13c is located. However, in the present invention, the location of the bulge 131 is not limited to this location. For example, the bulge may be provided at a location that is offset forward from the location where the lower end of the inclination on the front upper surface 13c is located, or at a location that is offset backward from the lower end.

[0053] Furthermore, in the above embodiment, the bulging portion 131 was configured to bulge inward in the vehicle width direction. However, in the present invention, the direction of bulging of the bulging portion is not limited to this. For example, it is also possible to provide a bulging portion that bulges outward in the vehicle width direction, or a bulging portion that bulges downward.

[0054] Furthermore, in the above embodiment, a bulge 131 is provided at one location on each torque box 13, but multiple bulges may be provided. In this case, the multiple bulges may be provided at substantially the same location in the longitudinal direction of the vehicle, distributed in the circumferential direction, or they may be provided at different locations in the longitudinal direction of the vehicle. [Explanation of Symbols]

[0055] 1 vehicle 11 Front side frame 12 Body Frame 13 Torque Box 16 Dash Panel 18 Floor Panels 131 Bulge 132 Ridge 141 Tunnel side member 161 Slope AR F heel position

Claims

1. A dashboard panel is provided to separate the passenger compartment of the vehicle from the front of the vehicle ahead of the passenger compartment, A pair of front side frames are provided, each positioned on both sides in the width direction of the front of the vehicle and extending in the longitudinal direction of the vehicle, A pair of body frames are provided, each connected to the pair of front side frames at its front end and extending in the longitudinal direction of the vehicle, A tunnel is provided in the central part of the vehicle width direction below the aforementioned passenger compartment, extending in the vehicle longitudinal direction, and having a shape that bulges upward, A pair of tunnel side members are provided along both sides of the tunnel in the vehicle width direction, extending in the vehicle longitudinal direction, with their respective front ends spaced rearward from the dash panel. A pair of torque boxes, each having a bag shape, are provided to connect the front portion of each of the body frames and the front portion of each of the tunnel side members, A floor panel is provided behind the aforementioned dash panel, extending in the vehicle width direction and the vehicle longitudinal direction, so as to cover the pair of tunnel side members and the pair of torque boxes, Equipped with, The rear of the aforementioned dashboard panel has an inclined portion that is provided to slope downwards gradually from front to rear, Each of the torque boxes is joined to the rear of the dash panel at its front, and has a bulge at the middle of the torque box in the vehicle's longitudinal direction, which bulges outward toward the bag shape. The bulging portion is provided such that, when a frontal impact load is applied to the torque box during a vehicle frontal collision, the portion of the torque box in front of the bulging portion becomes the starting point of a bending deformation in which it is displaced upward together with the inclined portion of the dash panel. The underbody structure of a vehicle.

2. Each of the torque boxes has a ridge on its outer surface that extends in the longitudinal direction of the vehicle. The aforementioned bulge is provided so as to cross the aforementioned ridge line. The underbody structure of a vehicle according to claim 1.

3. The aforementioned bulge is provided at a location in the vehicle's longitudinal direction that is spaced further forward than the front end of the tunnel side member. The underbody structure of a vehicle according to claim 1.

4. Each of the aforementioned torque boxes is The front portion to which the rear portion of the dash panel is joined has a front upper surface which is an upper surface composed of an inclined surface along the inclined portion of the dash panel, The bulging portion is provided at the location where the lower end of the inclination of the front upper surface is located in the longitudinal direction of the vehicle. An underbody structure for a vehicle according to any one of claims 1 to 3.

5. The aforementioned bulge is positioned in the longitudinal direction of the vehicle at a location forward of the heel position of an occupant seated in the front seat of the passenger compartment. An underbody structure for a vehicle according to any one of claims 1 to 3.

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