Vehicle undercarriage

Abstract

To obtain a vehicle understructure that can efficiently transmit the load of a side collision with a pole. [Solution] In the vehicle understructure 10, the first tunnel brace 36 is positioned at the rear of the first cross member 24, aligned with a ridge line L1 extending in the vehicle width direction and in the vehicle longitudinal direction, and the second tunnel brace 38 is positioned at the front of the second cross member 26, aligned with a ridge line L2 extending in the vehicle width direction and in the vehicle longitudinal direction.

Description

Technical Field

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

Background Art

[0002] The vehicle underbody structure disclosed in Patent Document 1 below includes a tunnel brace that connects the inside of the floor tunnel in the vehicle width direction.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above prior art, the arrangement of the tunnel brace for efficiently transmitting the load of a pole side collision is not considered.

[0005] In consideration of the above facts, an object of the present invention is to obtain a vehicle underbody structure capable of efficiently transmitting the load of a pole side collision.

Means for Solving the Problems

[0006] The vehicle understructure of the first embodiment comprises a rocker extending in the longitudinal direction of the vehicle at the side of the vehicle width direction of the underside of the vehicle, a hat-shaped floor tunnel extending in the longitudinal direction of the vehicle at the center of the vehicle width direction of the underside of the vehicle and convex upward when viewed in the longitudinal direction of the vehicle, a hat-shaped cross member connecting the rocker and the floor tunnel and convex upward when viewed from the side of the vehicle, and a tunnel brace connecting the inside of the floor tunnel in the vehicle width direction, dividing the space inside the floor tunnel vertically, and having a thickness in the longitudinal direction of the vehicle that is thinner than the width of the cross member in the longitudinal direction of the vehicle, wherein the cross member comprises a first cross member and a second cross member positioned further rearward than the first cross member, and the tunnel brace is composed of a first tunnel brace positioned at the rear of the first cross member with a ridge extending in the vehicle width direction and a position in the longitudinal direction of the vehicle, and a second tunnel brace positioned at the front of the second cross member with a ridge extending in the vehicle width direction and a position in the longitudinal direction of the vehicle.

[0007] In the first embodiment, the rocker and the floor tunnel are connected by a cross member. The tunnel brace, which connects the interior of the floor tunnel in the vehicle width direction, divides the space inside the floor tunnel vertically, and its thickness in the vehicle longitudinal direction is set to be thinner than the vehicle longitudinal width of the cross member. The cross member has a first cross member and a second cross member located further rearward than the first cross member. The tunnel brace is composed of a first tunnel brace positioned at the rear of the first cross member, aligned with the vehicle longitudinal position of a ridge extending in the vehicle width direction, and a second cross member positioned at the front of the second cross member, aligned with the vehicle longitudinal position of a ridge extending in the vehicle width direction. As a result, when a pole in a pole side impact test collides between the first and second cross members, the load that increases at the aforementioned ridges of the first and second cross members can be efficiently transmitted to the non-collision side via the first and second tunnel braces.

[0008] In the second embodiment of the vehicle understructure, the first tunnel brace and the second tunnel brace are each formed by joining together two members with an open cross-sectional shape that extends in the vehicle width direction.

[0009] In the second embodiment, since the first tunnel brace and the second tunnel brace are formed as described above, the first tunnel brace and the second tunnel brace can be made into a closed cross-section, and the bending rigidity of the first tunnel brace and the second tunnel brace can be increased.

[0010] The vehicle understructure of the third embodiment comprises, in the first or second embodiment, a first reinforcing member attached along the inner surface of the floor tunnel, and a second reinforcing member attached along the inner surface of the floor tunnel on the rearward side of the vehicle from the first reinforcing member, wherein the first tunnel brace is attached to the floor tunnel via the first reinforcing member, and the second tunnel brace is attached to the floor tunnel via the second reinforcing member.

[0011] In a third embodiment, the first tunnel brace is attached to the floor tunnel via a first reinforcing member mounted along the inner surface of the floor tunnel. The second tunnel brace is attached to the floor tunnel via a second reinforcing member mounted along the inner surface of the floor tunnel. Since the floor tunnel is reinforced by these first and second reinforcing members, deformation of the floor tunnel due to the load of a side collision of a vehicle can be suppressed.

[0012] In the fourth embodiment of the vehicle understructure, in the third embodiment, the first tunnel brace is fastened to the first reinforcing member at both ends in the vehicle width direction using two bolts, one above and one below, and the second tunnel brace is fastened to the second reinforcing member at both ends in the vehicle width direction using two bolts, one above and one below.

[0013] In the fourth embodiment, both ends of the first tunnel brace in the vehicle width direction are fastened to the first reinforcing member using two bolts, one above and one below, and both ends of the second tunnel brace in the vehicle width direction are fastened to the second reinforcing member using two bolts, one above and one below. This suppresses the generation of vertical moments, allowing the load of a pole side collision to be transmitted more efficiently to the non-collision side. [Effects of the Invention]

[0014] As described above, the vehicle understructure according to the present invention can efficiently transmit the load of a side collision with a pole. [Brief explanation of the drawing]

[0015] [Figure 1] This is a cross-sectional view showing a part of the vehicle understructure according to the embodiment. [Figure 2] This is a plan view showing a part of the vehicle understructure according to the embodiment. [Figure 3] This is a plan view showing the undercarriage of a vehicle according to the embodiment. [Figure 4] This is a bottom view showing the vehicle understructure according to the embodiment. [Figure 5] This is a first perspective view showing a part of the vehicle understructure according to the embodiment. [Figure 6] This is a second perspective view showing a part of the vehicle understructure according to the embodiment. [Figure 7] This is a cross-sectional view corresponding to Figure 1, illustrating load transfer in a pole side impact. [Figure 8] This is a plan view corresponding to Figure 2, illustrating the load transfer in a side impact with a pole. [Modes for carrying out the invention]

[0016] Hereinafter, the vehicle underbody structure 10 according to an embodiment of the present invention will be described with reference to FIGS. 1 to 8. In each figure, some reference numerals may be omitted for ease of viewing the drawing. Also, in FIGS. 1 and 7, the cross-hatching of the cross-section is omitted for ease of viewing the drawing. Further, the arrows FR, UP, and RH appropriately marked in each figure indicate the front direction (travel direction), upward direction, and right direction of the vehicle, respectively. Hereinafter, when simply using the directions of front, rear, left, right, up, and down for explanation, unless otherwise specified, it shall indicate the direction with respect to the vehicle.

[0017] (Configuration) As shown in FIGS. 1 to 3, the vehicle underbody structure 10 according to the present embodiment includes left and right rockers 12 extending in the front-rear direction on both sides in the vehicle width direction (both sides in the left-right direction) of the vehicle floor, a floor tunnel 18 extending in the front-rear direction at the center in the vehicle width direction (center in the left-right direction) of the vehicle floor, left and right floor panels 20 disposed between the left and right rockers 12 and the floor tunnel 18, left and right cross members 22 disposed on the upper surface side of the left and right floor panels 20 and connecting the left and right rockers 12 and the floor tunnel 18, and a tunnel brace 34 connecting the inside of the floor tunnel 18 in the vehicle width direction. As shown in FIG. 1, a battery 42 is disposed below the floor tunnel 18 and the left and right floor panels 20.

[0018] The left and right rockers 12 are composed of a rocker outer panel 14 disposed on the outer side in the vehicle width direction and a rocker inner panel 16 disposed on the inner side in the vehicle width direction. The rocker outer panel 14 and the rocker inner panel 16 are each composed of, for example, a press-formed steel plate and have a substantially hat-shaped cross-section with the sides facing each other in the front-rear direction being open. By joining these rocker outer panel 14 and rocker inner panel 16, each rocker 12 is formed in a hollow closed cross-section shape when viewed in the front-rear direction.

[0019] The floor tunnel 18 is constituted by, for example, a press-formed steel plate, and has a hat-shaped cross section that is convex upward when viewed in the longitudinal direction. This floor tunnel 18 has left and right side wall portions 18S facing each other in the left-right direction, an upper wall portion 18U connecting the upper end portions of the left and right side wall portions 18S in the left-right direction, and left and right flange portions 18F (see FIG. 5; reference numerals are omitted in FIGS. 1 and 7) extending outward in the vehicle width direction from the lower end portions of the left and right side wall portions 18S.

[0020] Between this floor tunnel 18 and the left and right rockers 12, left and right floor panels 20 are disposed. The left and right floor panels 20 are constituted by, for example, press-formed steel plates, and are in a plate shape with the vertical direction as the thickness direction. The left and right floor panels 20 have end portions on the outer side in the vehicle width direction joined to the left and right rockers 12, and end portions on the center side in the vehicle width direction joined to the left and right flange portions 18F of the floor tunnel 18.

[0021] Each of the left and right cross members 22 is constituted by a first cross member 24 and a second cross member 26 disposed on the rear side of the first cross member 24. The first cross member 24 and the second cross member 26 are constituted by, for example, press-formed steel plates, and have a hat-shaped cross section that is convex upward when viewed in the left-right direction. These first cross member 24 and second cross member 26 are seat cross members to which a front seat (not shown) is attached, and are joined to the upper surfaces of the respective floor panels 20. The first cross member 24 and the second cross member 26 form a closed cross section together with the respective floor panels 20.

[0022] The first cross member 24 and the second cross member 26 of the left cross member 22 are joined at their outer ends in the vehicle width direction to the rocker inner panel 16 of the left rocker 12, and at their central ends in the vehicle width direction to the left side wall portion 18S of the floor tunnel 18. The first cross member 24 and the second cross member 26 of the right cross member 22 are joined at their outer ends in the vehicle width direction to the rocker inner panel 16 of the right rocker 12, and at their central ends in the vehicle width direction to the right side wall portion 18S of the floor tunnel 18.

[0023] As shown in Figures 1 and 7, the rear of the first cross member 24 has two upper and lower ridges L1 extending in the vehicle width direction. Along these ridges L, the steel plate constituting the first cross member 24 is bent into a roughly L-shape in cross-section. Similarly, the front of the second cross member 26 has two upper and lower ridges L2 (see Figures 2 to 4) extending in the vehicle width direction. Along these ridges L2, the steel plate constituting the second cross member 26 is bent into a roughly L-shape in cross-section.

[0024] The tunnel brace 34 is composed of a first tunnel brace 36 and a second tunnel brace 38 positioned behind the first tunnel brace 36. The first tunnel brace 36 is fixed to the floor tunnel 18 via a first floor tunnel reinforcement 30, and the second tunnel brace 38 is fixed to the floor tunnel 18 via a second floor tunnel reinforcement 32. The first floor tunnel reinforcement 30 corresponds to the "first reinforcing member" in this invention, and the second floor tunnel reinforcement 32 corresponds to the "second reinforcing member" in this invention.

[0025] The first floor tunnel reinforcement 30 and the second floor tunnel reinforcement 32 are made of, for example, press-formed steel plates and have a roughly hat shape when viewed in the front-to-back direction. The first floor tunnel reinforcement 30 and the second floor tunnel reinforcement 32 are joined to the left and right side walls 18S, the top wall 18U, and the left and right flanges 18F of the floor tunnel 18, and are attached along the inner surface of the floor tunnel 18.

[0026] The first floor tunnel reinforcement 30 and the left and right first cross members 24 are positioned aligned in the front-to-back direction, and the second floor tunnel reinforcement 32 and the left and right second cross members 26 are positioned aligned in the front-to-back direction. The front-to-back width dimension of the first floor tunnel reinforcement 30 is set to be the same as the front-to-back width dimension of the left and right first cross members 24, and the front-to-back width dimension of the second floor tunnel reinforcement 32 is set to be the same as the front-to-back width dimension of the left and right second cross members 26.

[0027] The first tunnel brace 36 is constructed by joining two members 36A and 36B (see Figures 5 and 6), which are made of, for example, press-formed steel plates, and has an elongated shape with its longitudinal side in the vehicle width direction (left-right direction). The two members 36A and 36B have an open cross-sectional shape that extends in the vehicle width direction, while the first tunnel brace 36 has a closed cross-sectional shape that extends in the vehicle width direction. Similarly, the second tunnel brace 38 is constructed by joining two members 38A and 38B (see Figures 5 and 6), which are made of, for example, press-formed steel plates, and has an elongated shape with its longitudinal side in the vehicle width direction (left-right direction). The two members 38A and 38B have an open cross-sectional shape that extends in the vehicle width direction, while the second tunnel brace 38 has a closed cross-sectional shape that extends in the vehicle width direction.

[0028] The first tunnel brace 36 has a thickness in the longitudinal direction that is thinner than the width of the first cross member 24 in the longitudinal direction, and the second tunnel brace 38 has a thickness in the longitudinal direction that is thinner than the width of the second cross member 26 in the longitudinal direction. The first tunnel brace 36 and the second tunnel brace 38 are formed so that their vertical width decreases as they move towards the longitudinal center.

[0029] The first tunnel brace 36 is superimposed on the first floor tunnel reinforcement 30 from the rear at both ends in the vehicle width direction (both ends in the longitudinal direction). The first tunnel brace 36 is fastened and fixed to the first floor tunnel reinforcement 30 at both ends in the vehicle width direction using two upper and lower bolts 40 and two upper and lower nuts (not shown). The bolts 40 and nuts are arranged with the front-rear direction as the axial direction. Through this fastening and fixing, the left and right side walls 18S of the floor tunnel 18 are connected in the vehicle width direction via the first floor tunnel reinforcement 30 and the first tunnel brace 36. In addition, the first tunnel brace 36 divides the space inside the floor tunnel 18 into upper and lower sections.

[0030] The vehicle width direction ends (longitudinal direction ends) of the second tunnel brace 38 are overlapped with the second floor tunnel reinforcement 32 from the front. The vehicle width direction ends of the second tunnel brace 38 are fastened and fixed to the second floor tunnel reinforcement 32 using two upper and lower bolts 40 and two upper and lower nuts (not shown). The bolts 40 and nuts are arranged with the front-rear direction as the axial direction. Through this fastening and fixing, the left and right side walls 18S of the floor tunnel 18 are connected in the vehicle width direction via the second floor tunnel reinforcement 32 and the second tunnel brace 38. In addition, the space inside the floor tunnel 18 is divided vertically by this second tunnel brace 38.

[0031] The first tunnel brace 36 is positioned at the rear of the first cross member 24, aligned with the ridge line L1 extending in the vehicle width direction in the longitudinal direction. The second tunnel brace 38 is positioned at the front of the second cross member 26, aligned with the ridge line L2 extending in the vehicle width direction in the longitudinal direction. Furthermore, the vertical positional height of the center of gravity GC of the first cross member 24 and the center of gravity GT of the first tunnel brace 36 are the same. Similarly, the vertical positional height of the center of gravity (not shown) of the second cross member 26 and the center of gravity (not shown) of the second tunnel brace 38 are the same.

[0032] The two upper and lower bolts 40 that fasten the first tunnel brace 36 to the first floor tunnel reinforcement 30 are positioned separately on both sides in the vertical direction relative to the center of gravity GT of the first tunnel brace 36. Similarly, the two upper and lower bolts 40 that fasten the second tunnel brace 38 to the second floor tunnel reinforcement 32 are positioned separately on both sides in the vertical direction relative to the center of gravity of the second tunnel brace 38.

[0033] (Mechanism of Action and Effects) Next, the operation and effects of this embodiment will be described.

[0034] In the vehicle understructure 10 with the above configuration, the left and right rockers 12 and the floor tunnel 18 are connected by left and right cross members 22. The tunnel brace 34, which divides the space inside the floor tunnel 18 vertically, connects the inside of the floor tunnel 18 in the vehicle width direction. Each cross member 22 has a first cross member 24 and a second cross member 26, and the tunnel brace 34 has a first tunnel brace 36 and a second tunnel brace 38.

[0035] The first tunnel brace 36 is positioned at the rear of the first cross member 24, aligned with the upper and lower ridges L1 extending in the vehicle width direction, in the longitudinal direction, and the second tunnel brace 38 is positioned at the front of the second cross member 26, aligned with the upper and lower ridges L2 extending in the vehicle width direction, in the longitudinal direction.

[0036] Here, as shown in Figures 7 and 8, in the so-called neutral pole side impact test, the pole P impacts the vehicle at a longitudinal position between the first cross member 24 and the second cross member 26 on the side of the vehicle. At this time, the load becomes high on the upper and lower ridges L1 (especially the upper ridge L1) extending in the vehicle width direction at the rear of the first cross member 24 and on the upper and lower ridges L2 (especially the upper ridge L2) extending in the vehicle width direction at the front of the second cross member 26. This increased load can be efficiently transmitted to the non-impact side via the first tunnel brace 36 and the second tunnel brace 38 (see arrow F in Figures 7 and 8). As a result, deformation of the floor tunnel 18 can be suppressed, and a high impact load buildup can be achieved.

[0037] Furthermore, in this embodiment, the first tunnel brace 36 is formed by joining two open-section members 36A and 36B that extend in the vehicle width direction, and the second tunnel brace 38 is formed by joining two open-section members 38A and 38B that extend in the vehicle width direction. As a result, the first tunnel brace 36 and the second tunnel brace 38 form a closed cross-section, which increases the bending rigidity of the first tunnel brace 36 and the second tunnel brace 38. Consequently, deformation of the floor tunnel 18 can be further suppressed.

[0038] Furthermore, in this embodiment, the first tunnel brace 36 is attached to the floor tunnel 18 via a first floor tunnel reinforcement 30 that is mounted along the inner surface of the floor tunnel 18. Similarly, the second tunnel brace 38 is attached to the floor tunnel 18 via a second floor tunnel reinforcement 32 that is mounted along the inner surface of the floor tunnel 18. Since the floor tunnel 18 is reinforced by these first floor tunnel reinforcements 30 and second floor tunnel reinforcements 32, deformation of the floor tunnel 18 can be further suppressed.

[0039] Furthermore, in this embodiment, the vertical height of the center of gravity GC of the first cross member 24 and the center of gravity GT of the first tunnel brace 36 coincides, and the vertical height of the center of gravity of the second cross member 26 and the center of gravity of the second tunnel brace 38 coincides. With this configuration, the generation of vertical moments when loads from pole side collisions are transmitted from the first cross member 24 and the second cross member 26 to the first tunnel brace 36 and the second tunnel brace 38 is suppressed. As a result, the load from pole side collisions can be transmitted to the non-collision side more efficiently.

[0040] Furthermore, in this embodiment, the first floor tunnel reinforcement 30 and the left and right first cross members 24 are positioned aligned in the longitudinal direction, and the second floor tunnel reinforcement 32 and the left and right second cross members 26 are positioned aligned in the longitudinal direction. This suppresses the generation of longitudinal moments during load transmission in side collisions, thereby improving the efficiency of collision load transmission.

[0041] Furthermore, according to this embodiment, the first floor tunnel reinforcement 30 is fastened to the first tunnel brace 36 at both ends in the vehicle width direction using two bolts 40, one above and one below. Similarly, the second floor tunnel reinforcement 32 is fastened to the second tunnel brace 38 at both ends in the vehicle width direction using two bolts 40, one above and one below. Since these bolts 40 are arranged with the longitudinal direction as the axial direction, the fastening surfaces of each floor tunnel reinforcement 30, 32 can receive shear loads in the direction of transmission of lateral collision loads. As a result, deformation of the fastening surfaces is suppressed, and high load-bearing capacity can be achieved.

[0042] Furthermore, in this embodiment, the two upper and lower bolts 40 that fasten both ends of the first tunnel brace 36 in the vehicle width direction to the first floor tunnel reinforcement 30 are positioned separately on both sides in the vertical direction with respect to the center of gravity GT of the first tunnel brace 36. Similarly, the two upper and lower bolts 40 that fasten both ends of the second tunnel brace 38 in the vehicle width direction to the second floor tunnel reinforcement 32 are positioned separately on both sides in the vertical direction with respect to the center of gravity of the second tunnel brace 38. In other words, the center of gravity of each tunnel brace 36, 38 is set between the two upper and lower bolts 40 that serve as the transmission path for the load of a side collision with a pole, so that the generation of vertical moments can be suppressed. As a result, the load of a side collision with a pole can be transmitted to the non-collision side more efficiently.

[0043] In the above embodiment, the first tunnel brace 36 and the second tunnel brace 38 are attached to the floor tunnel 18 via the first floor tunnel reinforcement 30 and the second floor tunnel reinforcement 32, but the configuration is not limited to this. The first tunnel brace 36 and the second tunnel brace 38 may be directly attached to the floor tunnel 18.

[0044] Furthermore, the present invention can be implemented with various modifications without departing from its spirit. Of course, the scope of the present invention is not limited to the embodiments described above. [Explanation of Symbols]

[0045] 10. Vehicle understructure 12 Rocka 18 Floor Tunnel 18S side wall part 20 Floor Panels 22 Crossmember 24 First Crossmember 26 Second Crossmember 28 Floor Tunnel Reinforcement 30. First Floor Tunnel Reinforcement 32 Second Floor Tunnel Reinforcement 34 Tunnel brace 36 First Tunnel Brace 38 Second Tunnel Brace 40 volts GC center of gravity (center of gravity of the first cross member) GT Center of Gravity (Center of gravity of the first tunnel brace) L1 ridge (the ridge behind the first cross member) L2 ridge (the ridge in front of the second cross member)

Claims

1. A rocker extending in the longitudinal direction of the vehicle at the side of the vehicle width direction at the lower part of the vehicle, A hat-shaped floor tunnel extends in the longitudinal direction of the vehicle from the center of the vehicle width direction at the bottom of the vehicle, and is convex upwards when viewed in the longitudinal direction of the vehicle. Connecting the rocker and the floor tunnel, a hat-shaped cross member that protrudes upwards towards the vehicle when viewed from the side of the vehicle, A tunnel brace connects the interior of the floor tunnel in the vehicle width direction, divides the space inside the floor tunnel vertically, and has a thickness in the vehicle longitudinal direction that is thinner than the vehicle longitudinal width of the cross member, Equipped with, The aforementioned cross member is First cross member and, A second cross member is positioned on the rearward side of the vehicle from the first cross member, It has, The tunnel brace mentioned above is A first tunnel brace is positioned at the rear of the first cross member, with the ridge extending in the vehicle width direction aligned with the position in the vehicle longitudinal direction, A second tunnel brace is positioned at the front of the second cross member, with the ridge extending in the vehicle width direction aligned with the position in the vehicle longitudinal direction, The vehicle's understructure is composed of the following.

2. The vehicle understructure according to claim 1, wherein the first tunnel brace and the second tunnel brace are each formed by joining together two members having an open cross-sectional shape that extends in the vehicle width direction.

3. A first reinforcing member is attached along the inner surface of the floor tunnel, A second reinforcing member is attached to the rear side of the vehicle from the first reinforcing member, along the inner surface of the floor tunnel, Equipped with, The first tunnel brace is attached to the floor tunnel via the first reinforcing member, The vehicle understructure according to claim 1 or claim 2, wherein the second tunnel brace is attached to the floor tunnel via the second reinforcing member.

4. The first tunnel brace is fastened to the first reinforcing member at both ends in the vehicle width direction using two bolts, one above and one below. The vehicle understructure according to claim 3, wherein the second tunnel brace is fastened to the second reinforcing member at both ends in the vehicle width direction using two bolts, one above and one below.

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