Vehicle underbody structure

Abstract

The present invention provides a vehicle underbody structure that can suppress deformation of the front floor panel during a frontal collision while keeping manufacturing costs and vehicle weight increases to a minimum. [Solution] The vehicle 1 comprises a dash panel 16, a pair of front side frames 11, a pair of body frames 17, a tunnel 14, a pair of tunnel side frames, a floor panel 18, and a pair of reinforcing members 20. The pair of tunnel side frames are integrally provided with the tunnel 14 so as to extend in the front-rear direction along both sides of the tunnel 14 in the vehicle width direction, and have a U-shaped cross-section that bulges downward. The reinforcing members 20 have a bulging portion with an inverted U-shaped cross-section that bulges upward, and are positioned adjacent to the joint between the dash panel 16 and the floor panel 18, and are provided to form a closed cross-section in cooperation with a part of the longitudinal direction of the tunnel side frame with a part of the floor panel 18 sandwiched in between.

Description

Technical Field

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

Background Art

[0002] When a vehicle collides head-on, a part of the floor panel may be deformed by the backward movement of a power source mounted on the front part of the vehicle. A structure for suppressing deformation of a part of the floor panel during such a vehicle collision is disclosed in Patent Document 1.

[0003] Patent Document 1 discloses a structure for suppressing deformation of the floor panel at the foot area of a passenger seated on the rear seat of a vehicle. The structure disclosed in Patent Document 1 connects, with an extension having a hat-shaped cross section, a part where a closed cross-sectional structure is formed by a side member and a rein hose with the front side floor panel interposed therebetween, to a vertical wall portion that joins the front side floor panel and the rear side floor panel in a kick-up shape.

[0004] By the way, when a vehicle collides head-on, it is also necessary to suppress deformation of the floor panel at the foot area of a passenger seated on the front seat of the vehicle. In order to suppress deformation of the floor panel at the front part as described above, the structure disclosed in Patent Document 1 cannot be applied. That is, the structure of Patent Document 1 is premised on the presence of a vertical wall portion that joins the front side floor panel and the rear side floor panel, which are arranged in a stepped manner, in a kick-up shape, and it cannot be applied to the front part of the floor panel where such a vertical wall portion does not exist.

[0005] In conventional vehicles, in order to suppress deformation of the front floor panel during a head-on collision of the vehicle as described above, a structure has been adopted in which the tunnel side frame is formed using a high-strength material or the wall thickness is increased.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

[0007] However, as with the conventional vehicles described above, forming the tunnel side frames using high-strength materials or increasing their thickness would lead to increased manufacturing costs and vehicle weight, due to the long length of the tunnel side frames extending from the front to the rear of the vehicle.

[0008] The present invention aims to solve the above-mentioned problems and provides a vehicle underbody structure that can suppress deformation of the front floor panel during a frontal collision while keeping manufacturing costs and vehicle weight increases low. [Means for solving the problem]

[0009] An underbody structure for a vehicle according to one aspect of the present invention includes: 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 to each of the pair of front side frames at their front ends, 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; and a pair of frames provided integrally with the tunnel, extending in the vehicle width direction along both sides of the tunnel in the vehicle longitudinal direction, each having a U-shaped cross-sectional shape that opens upward and bulges downward. The vehicle comprises a tunnel side frame, a floor panel joined to the dash panel at its front end and extending in the width direction and front-rear direction below the passenger compartment, and a pair of reinforcing members positioned on top of a portion of the longitudinal direction of each of the tunnel side frames, with a portion of the floor panel sandwiched between them, and each having an upwardly bulging inverted U-shaped cross-section, wherein the front end of each of the reinforcing members is positioned adjacent to the joint between the dash panel and the floor panel rearward, and is positioned to form a closed cross-section with a portion of the longitudinal direction of the tunnel side frame with a portion of the floor panel sandwiched between them.

[0010] The underbody structure of the vehicle according to the above embodiment includes a reinforcing member that cooperates with a portion of the longitudinal direction of the tunnel side frame to form a closed section. The reinforcing member is positioned adjacent to the joint between the dash panel and the floor panel, but behind it. Here, the joint between the dash panel and the floor panel has higher strength than the area behind that joint. Therefore, the above underbody structure can induce a point of strain between the joint between the dash panel and the floor panel and the reinforcing member when a rearward impact load is transmitted to the body frame and the tunnel side frame during a vehicle frontal collision. Thus, by simply providing a reinforcing member that is joined to a portion of the longitudinal direction of the tunnel side frame, deformation of the floor panel during a vehicle frontal collision can be suppressed. Furthermore, since the above underbody structure only requires the provision of such a reinforcing member, it can reduce manufacturing costs and vehicle weight increases compared to cases where the tunnel side frame is formed using high-strength materials or its thickness is increased.

[0011] In the underbody structure of the vehicle according to the above embodiment, a driver's seat and an accelerator pedal positioned in front of the driver's seat are provided in the front part of the passenger compartment, and each of the reinforcing members may be positioned in the area between the driver's seat and the accelerator pedal in the front-rear direction.

[0012] The underbody structure of the vehicle according to the above embodiment has a reinforcing member placed in the area between the driver's seat and the accelerator pedal in the front-rear direction. A reinforcing member on the passenger side is also placed in the same area in the front-rear direction. The area where the reinforcing members are placed corresponds to the area where the feet (heels) of an occupant seated in the driver's or passenger's seat are placed. Therefore, by placing the reinforcing member in the above area, it is possible to suppress the upward deformation of the floor panel in that area during a frontal collision, thereby reducing the risk of ankle injury to the occupant.

[0013] In the underbody structure of the vehicle according to the above embodiment, each of the reinforcing members may have a main body portion on which the bulging portion is provided and which is arranged to overlap a part in the longitudinal direction of the tunnel side frame, and an extension portion which is provided to be continuous with the main body portion and to extend forward of the main body portion.

[0014] The underbody structure of the vehicle according to the above embodiment has an extended portion provided so that the reinforcing member extends forward from the main body, thereby preventing distortion from the body frame located on the outside in the vehicle width direction of the area where the reinforcing member is located from entering the tunnel side frame during a vehicle frontal collision. As a result, deformation of the floor panel during a vehicle frontal collision can be suppressed more reliably.

[0015] In the underbody structure of the vehicle according to the above embodiment, the extended portion may be provided with a bead that extends in the front-rear direction and bulges upward.

[0016] In the underbody structure of the vehicle according to the above embodiment, a bead is provided on the extended portion of the reinforcing member, so that a large section modulus can be secured for the extended portion of the reinforcing member. Therefore, in the above underbody structure, the intrusion of strain from the body frame into the tunnel side frame during a vehicle frontal collision can be suppressed more effectively.

[0017] In the underbody structure of the vehicle according to the above embodiment, the extended portion may be arranged to be further outward in the vehicle width direction than the main body portion.

[0018] In the underbody structure of the vehicle according to the above embodiment, reinforcing members are provided such that the extended portion is positioned outward in the vehicle width direction from the main body. Therefore, in the event of a frontal collision, the intrusion of distortion from the body frame can be suppressed at a point far in the vehicle width direction from where the tunnel side frame is located. Thus, in the above underbody structure, the intrusion of distortion from the body frame into the tunnel side frame during a frontal collision can be suppressed even more effectively.

[0019] In the underbody structure of the vehicle according to the above embodiment, each of the reinforcing members may be arranged spaced apart from the dash panel at a rearward angle.

[0020] In the underbody structure of the vehicle according to the above embodiment, the reinforcing members are positioned spaced rearward from the dash panel, so that the load applied during a frontal collision is distributed not only as shear force but also as bending force. Therefore, the above underbody structure is advantageous in maintaining the connection state of the reinforcing members to the lower members, and the load-bearing capacity of the joint portion of the reinforcing member can be improved.

[0021] In the underbody structure of the vehicle according to the above embodiment, a pair of torque boxes are further provided, each having a bag shape and being joined to the front part of each of the body frames, and extending inward in the vehicle width direction from the joining point, and each of the reinforcing members may be arranged so as to partially overlap with the torque boxes in a plan view.

[0022] In the underbody structure of the vehicle according to the above embodiment, the reinforcing members are arranged so as to overlap with the torque box in a plan view, thereby ensuring high strength against the load applied during a frontal collision. Therefore, the above underbody structure can more reliably suppress deformation of the floor panel in the area where the occupant's heel rests during a frontal collision.

[0023] In the underbody structure of the vehicle according to the above embodiment, a cross member is further provided which is positioned adjacent to the reinforcing member at the rear and extends in the vehicle width direction, and each of the reinforcing members may be positioned spaced apart in front of the cross member.

[0024] In the underbody structure of the vehicle according to the above aspect, since the reinforcing member is arranged at a distance forward from the cross member, even when a load in the vehicle width direction is input to the cross member during a side collision of the vehicle, stress concentration does not occur in a part of the reinforcing member. Further, in the above underbody structure, since the reinforcing member is arranged at a distance forward from the cross member, it is not necessary to make the dimensional accuracy of the member during manufacturing higher than necessary, and it is possible to suppress an increase in manufacturing cost.

Effect of the Invention

[0025] In the underbody structure of the vehicle according to each of the above aspects, it is possible to suppress deformation of the front floor panel during a frontal collision of the vehicle while suppressing an increase in manufacturing cost and vehicle weight.

Brief Description of the Drawings

[0026] [Figure 1] It is a bottom view of a part of the underbody structure of the vehicle according to the embodiment as viewed from the lower side of the vehicle. [Figure 2] It is a top view of a part of the underbody structure of the vehicle as viewed from the upper side of the vehicle. [Figure 3] It is a cross-sectional view showing a cross section taken along line III-III in FIG. 2. [Figure 4] It is a top view showing the positional relationship between the driver's seat, the accelerator pedal, and the reinforcing member. [Figure 5] It is an enlarged top view showing an enlarged view of the portion indicated by arrow A in FIG. 4. [Figure 6] It is a top view showing the structure of the reinforcing member. [Figure 7] It is a schematic diagram showing the strain in the floor when a frontal collision load is input. [Figure 8] It is a top view showing the structure of the reinforcing member according to Example 2. [Figure 9] It is a diagram for explaining the role played by the bead when a frontal collision load is input.

Mode for Carrying Out the Invention

[0027] Embodiments of the present invention will be described below with reference to the drawings. The embodiments described below are illustrative examples of the present invention, and the present invention is not limited to these embodiments except for its essential configuration.

[0028] 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. In all directions, the occupants are used as the reference point.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] Vehicle 1 also includes a pair of torque boxes 13, a tunnel 14, a floor panel 18, and a pair of cross members 19, all located beneath the passenger compartment 1a. Each of the pair of torque boxes 13 is joined to the front of each of the pair of body frames 12 and extends inward in the vehicle width direction from the joining point. Each torque box 13 has a bag-like (box-like) shape.

[0033] The tunnel 14 is located below the passenger compartment 1a, extending in the vehicle's longitudinal direction from the center in the vehicle width direction, and has a shape that bulges upward (towards the passenger compartment). The floor panel 18 is joined to the dash panel 16 at its front end and is located below the passenger compartment 1a, extending in both the vehicle width direction and the vehicle's longitudinal direction. In the vehicle 1 according to this embodiment, the floor panel 18 is divided into left and right sides in the vehicle width direction, with the tunnel 14 as the boundary. Each of the pair of cross members 19 is provided to extend outward in the vehicle width direction from the tunnel 14. Each cross member 19 is joined to the side sill 15 on the outside in the vehicle width direction. In Figure 2, only the pair of cross members 19 located furthest forward in the vehicle's longitudinal direction are shown, but in the vehicle 1, multiple pairs of cross members 19 are provided spaced apart from each other in the vehicle's longitudinal direction.

[0034] Furthermore, the vehicle 1 includes a pair of tunnel side frames 141 and a pair of reinforcing members 20. Each of the pair of tunnel side frames 141 is provided to extend in the longitudinal direction of the vehicle along both sides of the tunnel 14 in the vehicle width direction. Each tunnel side frame 141 has a U-shaped cross-section that opens upward (towards the back of the page in Figure 1) and recesses downward (towards the front of the page in Figure 1). As will be described in detail later, in the vehicle 1 according to this embodiment, the tunnel side frames 141 are provided integrally with the tunnel 14.

[0035] As shown in Figure 2, each of the pair of reinforcing members 20 is positioned between the dash panel 16 and the cross member 19 in the longitudinal direction of the vehicle and is provided to overlap a portion of the tunnel side frame 141.

[0036] The reinforcing member 20 is positioned at a rearward distance from the dash panel 16. In other words, the reinforcing member 20 is positioned adjacent to the dash panel 16 and at a distance from the point where the dash panel 16 and the floor panel 18 are joined. The detailed structure of the reinforcing member 20 will be described later.

[0037] 2. Arrangement structure of the reinforcing member 20 to the tunnel side frame 141 The arrangement structure of the reinforcing member 20 to the tunnel side frame 141 will be explained with reference to Figure 3.

[0038] As shown in Figure 3, the tunnel side frame 141 is integrally provided with the tunnel 14. Therefore, the plate thickness t2 of the tunnel side frame 141 satisfies the relationship t2=t1 or t2≈t1 with respect to the plate thickness t1 of other parts of the tunnel 14. Note that the difference between t2≈t1 is within the range of manufacturing tolerance. Specifically, although the plate thickness changes in each region due to pressing, etc., this change in plate thickness is allowed to be considered approximately the same.

[0039] The reinforcing member 20 has a bulging portion 20a that bulges upward. The bulging portion 20a of the reinforcing member 20 is positioned on the tunnel side frame 141. The tunnel side frame 141 and the reinforcing member 20 are joined to each other with a portion of the floor panel 18 sandwiched between them. As a result, the tunnel side frame 141 and the reinforcing member 20 form a closed cross-section at the portion where they are joined to each other.

[0040] 3. Arrangement of reinforcing members 20 in the longitudinal direction of the vehicle The arrangement of the reinforcing members 20 in the longitudinal direction of the vehicle will be explained using Figures 4 to 6. Note that in Figure 4, only the driver's seat 21 is shown for convenience, but in vehicle 1, the passenger seat is also located at the same position in the longitudinal direction of the vehicle within the passenger compartment 1a.

[0041] As shown in Figure 4, the driver's seat 21 is located in the passenger compartment 1a on one side in the vehicle width direction relative to the tunnel 14. The driver's seat 21 is located in the area extending towards the rear from above the cross member 19, which is located at the very front of the vehicle in the longitudinal direction.

[0042] In the passenger compartment 1a, the accelerator pedal 22 is located in the inner part of the vehicle width direction, in front of the driver's seat 21 and close to the tunnel 14. The driver, seated in the driver's seat 21, operates the accelerator pedal 22 by placing their heel slightly behind the accelerator pedal 22 on the floor panel 18.

[0043] As shown in Figures 4 and 5, the reinforcing member 20 is positioned in the longitudinal direction of the vehicle, behind the location of the accelerator pedal 22 and in front of the cross member 19. As shown in Figure 5, in the longitudinal direction of the vehicle, the bulging portion 20a of the reinforcing member 20, which is positioned on the tunnel side frame 141, is spaced further back than the accelerator pedal 22, and a portion of it overlaps with the rear end of the torque box 13 (indicated by arrow B in Figure 5).

[0044] As shown in Figure 6, the reinforcing member 20 is positioned such that its rear end 20b is spaced forward from the cross member 19, leaving a gap G (indicated by arrow C in Figure 6). In other words, the reinforcing member 20 is neither in contact with nor joined to the cross member 19.

[0045] Furthermore, the arrangement of the reinforcing member 20 on the side where the passenger seat is located in the vehicle width direction is the same as described above in the vehicle's longitudinal direction.

[0046] 4. Detailed structure of the reinforcing member 20 The detailed structure of the reinforcing member 20 will be explained with reference to Figure 6. Note that Figure 6 only shows the reinforcing member 20 located on the driver's seat 21 side, but the reinforcing member 20 located on the passenger seat side has a structure that is symmetrical to the reinforcing member 20 on the driver's seat 21 side.

[0047] As shown in Figure 6, the reinforcing member 20 has a main body portion 201 and an extension portion 202 that is provided continuously with the main body portion 201. The main body portion 201 is a portion that is placed on top of a part of the longitudinal direction of the tunnel side frame 141 (see Figure 3, etc.) and has an upwardly bulging portion 20a formed thereon. The main body portion 201 also has joint portions 204 and 205 that are joined to the tunnel side frame 141 (see Figure 3, etc.) with the floor panel 18 (see Figure 3, etc.) in between. The joining method is, for example, resistance spot welding or laser welding.

[0048] The extension portion 202 is provided to extend diagonally forward from the outer portion in the vehicle width direction at the front of the main body portion 201. In other words, the extension portion 202 is positioned offset to the outer side in the vehicle width direction from the main body portion 201. Furthermore, the extension portion 202 is provided to extend further forward than the main body portion 201.

[0049] The extension 202 has a joint 206 that is joined to the torque box 13 (see Figure 2, etc.) with the floor panel 18 (see Figure 2, etc.) in between, and a bead 203 that is provided to bulge upward and extend in the longitudinal direction of the vehicle. The bead 203 is formed over substantially the entire area of ​​the extension 202 in the longitudinal direction of the vehicle.

[0050] 5. Floor distortion when a forward thrust load is applied. The results of the verification of floor strain when a forward thrust load is applied will be explained using Figures 7 and 8.

[0051] For verification, the following three types of samples were prepared.

[0052] (1) Example 1 A sample having the same structure as vehicle 1 according to this embodiment was designated as Example 1.

[0053] (2) Example 2 Example 2 is a sample equipped with the reinforcing member 120 shown in Figure 8. Specifically, the reinforcing member 120 in Example 2, like the reinforcing member 20, has a main body portion 121 and an extension portion 126 integrally formed. In the reinforcing member 120, the rear end portion 120b of the main body portion 121 extends further rearward than the main body portion 201 of the reinforcing member 20 (rear extension portion 120d), and the front end portion 120c of the extension portion 126 extends forward (front extension portion 120e). Therefore, the rear end portion 120b of the reinforcing member 120 is connected to the cross member 19, and the front end portion 120c or its vicinity is connected to the dash panel 16.

[0054] (3) Comparative Example A comparative example was provided for the structure of the vehicle 1 according to this embodiment, but without the reinforcing member 20.

[0055] For each of the above-described examples 1 and 2 and comparative examples, the strain on the floor when a forward thrust load was applied was measured. Figure 7 illustrates the strain lines for each sample based on the measurement results.

[0056] As shown in Figure 7, in Embodiment 1, the strain line extends outward in the vehicle width direction, passing in front of the reinforcing member 20, and runs along the floor frame 17 (body frame 12). In Embodiment 1, as described above, a portion of the extended portion 202 is positioned to overlap with the torque box 13, so as shown in the lower part of Figure 7, when a moment is applied, the strain line from the deformation starting point to the location of the front end of the extended portion 202 does not align in the vehicle width direction as in the comparative example, but runs along the floor frame 17 (body frame 12).

[0057] On the other hand, in Example 2, as explained with reference to Figure 8, the front end portion 120c is connected to the dash panel 16, so when a forward thrust load is applied, a shear force acts on the joint between the reinforcing member 120 and the tunnel side frame 141. In contrast, in Example 1, the reinforcing member 20 is positioned rearward and spaced apart from the dash panel 16, so the forward thrust load is distributed into shear force and compressive force. Therefore, Example 1 achieves improved load-bearing capacity at the joint compared to Example 2.

[0058] Furthermore, in Example 2, since the rear end portion 120b is connected to the cross member 19, there is a risk that a compressive force will act on it and cause deformation if a forward impact load is applied. Also, there is a concern that stress concentration will occur if a side impact load is applied to Example 2, which could become the starting point for breakage. In contrast, in Example 1, the reinforcing member 20 is positioned forward and spaced apart from the cross member 19 (leaving a gap G), so that a compressive load does not act on it when a forward impact load is applied, and the occurrence of a breakage starting point due to stress concentration when a side impact load is applied is suppressed.

[0059] 6. Effects of providing the bead 203 on the extended portion 202 In the vehicle 1 according to this embodiment, a bead 203 is provided on the extended portion 202 of the reinforcing member 20. The effect of this will be explained with reference to Figure 9.

[0060] As shown in Figure 9, when forward loads F1 and F2 are applied, strain enters the reinforcing member 20 from the floor frame 17 and the body frame 12 below it (see Figure 1) (strain enters as shown by D). In this case, since the reinforcing member 20 has a bead 203 on the extended portion 202, the section modulus can be secured, and the intrusion of strain into the vehicle width direction inward from the bead 203 on the extended portion 202 and into the main body portion 201 is suppressed.

[0061] Therefore, because the reinforcing member 20 has a bead 203 on the extended portion 202, even when a forward thrust load is applied, distortion from the floor frame 17 and body frame 12 is less likely to penetrate the main body portion 201, etc.

[0062] 7. Effects The underbody structure of vehicle 1 according to this embodiment includes a reinforcing member 20 that cooperates with a portion of the longitudinal direction of the tunnel side frame 141 to form a closed cross-section. The reinforcing member 20 is positioned adjacent to and spaced rearward from the joint between the dash panel 16 and the floor panel 18. Here, the joint between the dash panel 16 and the floor panel 18 has higher strength than the area behind that portion. Therefore, when a rearward impact load is transmitted to the body frame 12 and the tunnel side frame 141 during a vehicle frontal collision, the vehicle 1 can induce a point of strain between the joint between the dash panel 16 and the floor panel 18 and the reinforcing member 20. Thus, by simply providing a reinforcing member 20 that is joined to a portion of the longitudinal direction of the tunnel side frame 141, deformation of the floor panel 18 during a vehicle frontal collision can be suppressed. Furthermore, since vehicle 1 only requires the provision of a reinforcing member 20, it is possible to reduce manufacturing costs and vehicle weight increases compared to cases where the tunnel side frame 141 is formed using a high-strength material or its thickness is increased.

[0063] Furthermore, in the underbody structure of the vehicle 1 according to this embodiment, a reinforcing member 20 is positioned in the area between the driver's seat 21 and the accelerator pedal 22 in the longitudinal direction of the vehicle. A reinforcing member 20 on the passenger side is also positioned in the same area in the longitudinal direction of the vehicle. The area in which the reinforcing members 20 are positioned corresponds to the area where occupants seated in the driver's seat 21 or passenger seat place their feet (heels). Therefore, by positioning the reinforcing members 20 in the area, it is possible to suppress the upward deformation of the floor panel 18 in that area during a frontal collision, thereby reducing the risk of ankle injury to the occupant.

[0064] Furthermore, the underbody structure of the vehicle 1 according to this embodiment has an extended portion 202 provided such that the reinforcing member 20 extends forward of the main body portion 201. This prevents distortion from the floor frame 17 and body frame 12 located on the outside in the vehicle width direction of the area where the reinforcing member 20 is located from entering the tunnel side frame 141 during a vehicle frontal collision. As a result, deformation of the floor panel 18 during a vehicle frontal collision can be suppressed more reliably.

[0065] Furthermore, in the underbody structure of the vehicle 1 according to this embodiment, a bead 203 is provided on the extended portion 202 of the reinforcing member 20, which allows for a large section modulus of the extended portion 202 of the reinforcing member 20. Therefore, in the vehicle 1, the intrusion of strain from the floor frame 17 and body frame 12 into the tunnel side frame 141 during a vehicle frontal collision can be more effectively suppressed.

[0066] Furthermore, in the underbody structure of vehicle 1 according to this embodiment, the reinforcing member 20 is provided such that the extended portion 202 is positioned further outward in the vehicle width direction than the main body portion 201. Therefore, in the event of a vehicle frontal collision, the intrusion of distortion from the floor frame 17 and body frame 12 can be suppressed at a location far from the location where the tunnel side frame 141 is positioned in the vehicle width direction. Thus, in vehicle 1, the intrusion of distortion from the floor frame 17 and body frame 12 into the tunnel side frame 141 in the event of a vehicle frontal collision can be suppressed even more effectively.

[0067] Furthermore, in the underbody structure of the vehicle 1 according to this embodiment, the reinforcing member 20 is positioned at a rearward distance from the dash panel 16, so that the load applied during a frontal collision is distributed not only as shear force but also as bending force. Therefore, in the vehicle 1, it is advantageous to maintain the connection state of the reinforcing member 20 to the floor panel 18 and tunnel side frame 141, and the load-bearing capacity of the connection portion of the reinforcing member 20 can be improved.

[0068] Furthermore, in the underbody structure of the vehicle 1 according to this embodiment, the reinforcing member 20 is arranged so as to overlap with the torque box 13 in a plan view, thereby ensuring high strength against the load applied during a vehicle frontal collision. As a result, the deformation of the floor panel 18 (upward bulging deformation) at the point where the occupant's heel rests during a vehicle frontal collision can be more reliably suppressed.

[0069] Furthermore, in the underbody structure of the vehicle 1 according to this embodiment, the reinforcing member 20 is positioned forward and spaced apart from the cross member 19. Therefore, even if a load in the vehicle width direction (side impact load) is applied to the cross member 19 during a side collision, stress concentration does not occur in any part of the reinforcing member 20. In addition, since the reinforcing member 20 is positioned forward and spaced apart from the cross member 19 in the vehicle 1, it is not necessary to make the dimensional accuracy of the members unnecessarily high during manufacturing, and it is possible to suppress an increase in manufacturing costs.

[0070] As described above, the underbody structure of the vehicle 1 according to this embodiment can suppress deformation of the front floor panel 18 during a frontal collision (in particular, deformation of the part where the heels of occupants seated in the driver's seat 21 or passenger seat rest) while keeping manufacturing costs and vehicle weight increases to a minimum.

[0071] [Differentiation] In the above embodiment, the reinforcing member 20 is placed in the area between the accelerator pedal 22 and the driver's seat 21 in the longitudinal direction of the vehicle, and the same reinforcing member 20 is also placed in the same area in the longitudinal direction of the vehicle on the passenger side. However, in the present invention, the reinforcing member may be placed in a wider area in the longitudinal direction that includes the above area. For example, the reinforcing member 120 as in the above embodiment 2 may be used.

[0072] In the above embodiment, the reinforcing member 20 has an extended portion 202 that extends forward from the main body portion 201, but the present invention is not limited thereto. For example, the main body portion 201 having a bulging portion 20a may extend forward to the vicinity of the dash panel 16, and may not have an extended portion.

[0073] In the above embodiment, a configuration was adopted in which a bead 203 is provided on the extended portion 202 of the reinforcing member 20, but in the present invention, it is not necessarily required that a bead 203 be provided on the extended portion 202.

[0074] In the above embodiment, the extended portion 202 of the reinforcing member 20 is configured to be offset outward in the vehicle width direction from the main body portion 201. However, in the present invention, the extended portion 202 does not necessarily have to be offset outward in the vehicle width direction from the main body portion 201. For example, a rectangular or trapezoidal reinforcing member can be used when viewed from above.

[0075] In the above embodiment, the reinforcing member 20 is positioned spaced rearward from the dash panel 16. However, in the present invention, the reinforcing member may overlap with the dash panel in a top view, as in Embodiment 2 above. In other words, the reinforcing member may overlap with the joint between the dash panel and the floor panel in a top view.

[0076] In the above embodiment, the reinforcing member 20 is positioned forward and spaced apart from the cross member 19. However, in the present invention, the reinforcing member may be in contact with the cross member (gap G=0), as in the above embodiment 2. [Explanation of Symbols]

[0077] 1 vehicle 11 Front side frame 12 Body Frame 13 Torque Box 14 Tunnel 16 Dash Panel 18 Floor Panels 19 Crossmember 20,120 Reinforcement members 21 Driver's seat 22 Accelerator pedal 121,201 Main body 126,202 Extension part 141 Tunnel Side Frame 201 Main body 203 Bead

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 front-rear direction and having a shape that bulges upward, A pair of tunnel side frames are integrally provided with the tunnel so as to extend in the longitudinal direction along both sides of the tunnel in the vehicle width direction, and each has a U-shaped cross-section that opens upward and bulges downward, A floor panel is provided that is joined to the dash panel at its front end and extends in the width direction and front-rear direction below the passenger compartment, With a portion of the floor panel sandwiched between the tunnel side frame, a pair of reinforcing members are arranged to overlap a portion of the tunnel side frame in the longitudinal direction, and each has an upwardly bulging inverted U-shaped cross-section. Equipped with, Each of the reinforcing members is positioned such that its front end is located at a location adjacent to the joint between the dash panel and the floor panel, and is provided to form a closed cross-section with a portion of the longitudinal direction of the tunnel side frame, with a portion of the floor panel in between. The underbody structure of a vehicle.

2. At the front of the aforementioned passenger compartment are the driver's seat and the accelerator pedal positioned in front of the driver's seat. Each of the reinforcing members is positioned in the region between the driver's seat and the accelerator pedal in the front-rear direction. The underbody structure of a vehicle according to claim 1.

3. Each of the reinforcing members has a main body portion on which the bulging portion is provided and which is arranged to overlap a part of the longitudinal direction of the tunnel side frame, and an extension portion which is provided to be continuous with the main body portion and to extend forward of the main body portion. The underbody structure of a vehicle according to claim 1.

4. The extended portion is provided with a bead that extends in the front-rear direction and bulges upward. The underbody structure of a vehicle according to claim 3.

5. The aforementioned extension is positioned further outward in the vehicle width direction than the main body. The underbody structure of a vehicle according to claim 3.

6. Each of the reinforcing members is positioned spaced apart from the dash panel at the rear. The underbody structure of a vehicle according to claim 1.

7. Each of the aforementioned body frames is joined to the front portion, and is provided so as to extend inward in the vehicle width direction from the joining portion, and further comprises a pair of torque boxes, each having a bag shape, Each of the reinforcing members is positioned such that, in a plan view, it partially overlaps with the torque box. The underbody structure of a vehicle according to claim 1.

8. The vehicle further comprises a cross member positioned adjacent to the aforementioned reinforcing member at the rear and extending in the vehicle width direction, Each of the reinforcing members is positioned forward and spaced apart from the cross member. An underbody structure for a vehicle according to any one of claims 1 to 7.

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