Vehicle lower structure

Abstract

To provide a vehicle lower structure capable of improving collision safety performance in a structure in which a battery frame functions as a frame of a vehicle body.SOLUTION: A vehicle lower structure includes: a battery frame 12 configured to include side portions 14 provided as a pair of right and left portions and each extending in a vehicle front-rear direction and a cross portion 16 extending in a vehicle width direction and coupling the rear ends of the side portions 14 to each other, the battery frame surrounding a battery 100; and rear side frames 20 provided as a pair of right and left portions thereof and each extending in the vehicle front-rear direction, and having front end portions thereof being connected to the battery frame 12, where the rear side frames 20 are configured to include a first fixing portion P1 that is fixed to the cross portion 16 and a second fixed portion P2 that is fixed to the rear end surface 14B of the side portion 14 on an outer side of the vehicle width direction rather than the first fixing portion P1.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] Patent Document 1 discloses a battery frame that surrounds a battery. The battery frame of this Patent Document 1 constitutes the frame of the vehicle body.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, side frames extending in the vehicle longitudinal direction are connected to the front and rear of the vehicle body frame, respectively. However, in the structure described in Patent Document 1 above, when the vehicle collides, a load is input from the side frame to the battery frame, causing a moment to act, and it may not be possible to maintain a good fixed state between the side frame and the battery frame.

[0005] An object of the present invention is to obtain a vehicle underbody structure capable of improving collision safety performance in a structure in which a battery frame functions as a vehicle body frame.

Means for Solving the Problems

[0006] The vehicle underbody structure according to claim 1 includes a pair of left and right side portions provided and extending in the vehicle longitudinal direction respectively, and a cross portion extending in the vehicle width direction and connecting the rear ends of the side portions, and is configured to include a battery frame surrounding the battery, and a pair of left and right rear side frames provided and extending in the vehicle longitudinal direction respectively with the front end portions connected to the battery frame. The rear side frame includes a first fixing portion fixed to the cross portion and a second fixing portion fixed to the rear end surface of the side portion outside the vehicle width direction of the first fixing portion.

[0007] In the vehicle underbody structure according to claim 1, the battery frame includes the side portions and the cross portion. The side portions are provided in a pair on the left and right and extend in the vehicle longitudinal direction respectively. The cross portion extends in the vehicle width direction and connects the rear ends of the side portions. Also, the rear side frame is connected to the battery frame. In this way, by connecting the rear side frame to the battery frame, the load at the time of a rear collision (rear-end collision) can be transmitted to the battery frame, and the battery frame functions as the frame of the vehicle body.

[0008] Also, the rear side frame is provided in a pair on the left and right, and includes a first fixing portion fixed to the cross portion of the battery frame and a second fixing portion fixed to the rear end surface of the side portion of the battery frame outside the vehicle width direction of the first fixing portion. Thereby, even when a moment acts on the rear side frame at the time of a rear-end collision and a force acts in a direction separating from the side portion of the battery frame with respect to the rear side frame, since the rear side frame is fixed to the rear end surface of the side portion by the second fixing portion, the fixed state between the rear side frame and the battery frame can be maintained.

[0009] The vehicle underbody structure according to claim 2 is, in claim 1, the both end portions in the vehicle width direction of the cross portion are inclined portions inclined so as to be located on the vehicle front side in a plan view as they go toward the outside in the vehicle width direction.

[0010] In the vehicle underbody structure according to claim 2, since the inclined portion of the cross portion is inclined so as to be located on the vehicle front side as it goes outward in the vehicle width direction in plan view, the collision load at the time of rear impact can be efficiently transmitted to the side portion through the inclined portion.

[0011] The vehicle underbody structure according to claim 3 is, in claim 2, wherein the first fixing portion is provided at a connection portion between a straight portion linearly extending in the vehicle width direction in the cross portion and the inclined portion.

[0012] In the vehicle underbody structure according to claim 3, the first fixing portion is provided at a connection portion between the inclined portion and the straight portion. Thereby, the load input from the rear side frame to the battery frame can be transmitted to both the inclined portion and the straight portion.

[0013] The vehicle underbody structure according to claim 4 is, in claim 3, wherein the rear side frame extends rearward in the vehicle from the connection portion in plan view.

[0014] In the vehicle underbody structure according to claim 4, the collision load transmitted from the side frame to the battery frame can be received by the first fixing portion.

[0015] The vehicle underbody structure according to claim 5 includes a pair of left and right side portions each extending in the vehicle longitudinal direction, a cross portion extending in the vehicle width direction and connecting the front ends of the side portions, a battery frame surrounding the battery, and a pair of left and right front side frames each extending in the vehicle longitudinal direction and having a rear end connected to the battery frame. The front side frame includes a first fixing portion fixed to the cross portion and a second fixing portion fixed to the front end surface of the side portion outside the vehicle width direction of the first fixing portion.

[0016] In the vehicle underbody structure according to claim 5, the battery frame is configured to include side portions and a cross portion. A pair of left and right side portions are provided and each extends in the vehicle longitudinal direction. The cross portion extends in the vehicle width direction and connects the rear ends of the side portions. Further, a front side frame is connected to the battery frame. In this way, by connecting the front side frame to the battery frame, the load during a frontal collision (front impact) can be transmitted to the battery frame, and the battery frame functions as the frame of the vehicle body.

[0017] Further, a pair of left and right front side frames are provided, and each includes a first fixing portion fixed to the cross portion of the battery frame and a second fixing portion fixed to the rear end surface of the side portion of the battery frame outside the vehicle width direction from the first fixing portion. Thereby, even when a moment acts on the front side frame during a front impact and a force acts in a direction away from the side portion of the battery frame with respect to the front side frame, since the front side frame is fixed to the rear end surface of the side portion by the second fixing portion, the fixing state between the front side frame and the battery frame can be maintained.

Advantages of the Invention

[0018] As described above, according to the vehicle underbody structure of the present invention, in the structure in which the battery frame functions as the frame of the vehicle body, the collision safety performance can be improved.

Brief Description of the Drawings

[0019]

Figure 1

Figure 2

Figure 3

Figure 4

Best Mode for Carrying Out the Invention

[0020] <First Embodiment> The vehicle underbody structure according to the first embodiment will be described with reference to the drawings.

[0021] FIG. 1 is a plan view schematically showing a main part of a vehicle 10 to which the vehicle underbody structure according to the embodiment is applied. In the figure, the arrows FR, UP, and RH indicate the vehicle front direction, the vehicle upward direction, and the vehicle right direction in the vehicle 10, respectively. In the following description, when the front-rear, up-down, and left-right directions are used without special mention, they indicate the front and rear in the vehicle front-rear direction, the up and down in the vehicle up-down direction, and the left and right in the vehicle left-right direction (width direction), respectively.

[0022] As shown in FIG. 1, the vehicle 10 to which the vehicle underbody structure of the present embodiment is applied includes a battery frame 12 and a rear side frame 20. The battery frame 12 is a frame that surrounds the battery 100 and includes a side portion 14 and a cross portion 16.

[0023] A pair of left and right side portions 14 are provided and extend in the vehicle front-rear direction respectively. The side portion 14 may be formed in a closed cross-sectional shape by stacking steel plates, or may be formed by extrusion molding or the like. It may also be formed by casting or the like. For example, the right side portion 14 extends along the right side surface of the battery 100, and the left side portion 14 extends along the left side surface of the battery 100.

[0024] The cross portion 16 extends in the vehicle width direction and connects the rear ends of the side portions 14 to each other. The front ends of the side portions 14 are also connected in the vehicle width direction by a cross portion (not shown) similar to the cross portion 16. In the present embodiment, as an example, the cross portion 16 is integrally formed with the side portion 14. For example, the side portion 14 and the cross portion 16 may be integrally formed by casting or the like.

[0025] Here, the cross portion 16 is configured to include a straight portion 16A and an inclined portion 16B. The straight portion 16A is provided at the center in the vehicle width direction of the cross portion 16 and extends in the vehicle width direction.

[0026] The inclined portion 16B is provided at both end portions in the vehicle width direction of the cross portion 16 and is inclined in a plan view so as to be positioned on the vehicle front side as it goes toward the outside in the vehicle width direction. Specifically, the inclined portion 16B located at the right end portion of the cross portion 16 has its left end connected to the straight portion 16A and is inclined toward the vehicle front side from the left end toward the right end. And the right end of this inclined portion 16B is connected to the rear end of the side portion 14.

[0027] On the other hand, the inclined portion 16B located at the left end portion of the cross portion 16 has its right end connected to the straight portion 16A and is inclined toward the vehicle front side from the right end toward the left end. And the left end of this inclined portion 16B is connected to the rear end of the side portion 14.

[0028] A pair of left and right rear side frames 20 are provided and each extends in the vehicle front-rear direction. Also, the front end portion of the rear side frame 20 is connected to the battery frame 12.

[0029] The rear side frame 20 may be formed, for example, by stacking steel plates into a closed cross-sectional shape, or may be formed by extrusion molding or the like. Also, it may be formed by casting or the like. Further, the rear side frame 20 may be connected in the vehicle width direction by a cross member (not shown). In this case, the cross member and the left and right rear side frames 20 may be integrally formed.

[0030] Here, each of the pair of left and right rear side frames 20 is configured to include a front-rear extending portion 20A, a cross fastening portion 20B, and a side fastening portion 20C. In this embodiment, as an example, the front-rear extending portion 20A, the cross fastening portion 20B, and the side fastening portion 20C are integrally formed.

[0031] The front and rear extending portion 20A on the right side extends in the vehicle front-rear direction, and the front end portion of the front and rear extending portion 20A is located at the connection portion (boundary portion) between the straight portion 16A and the right inclined portion 16B of the cross portion 16 in the battery frame 12 in plan view. Also, the front and rear extending portion 20A on the left side extends in the vehicle front-rear direction, and the front end portion of the front and rear extending portion 20A is located at the connection portion (boundary portion) between the straight portion 16A and the left inclined portion 16B of the cross portion 16 in the battery frame 12 in plan view.

[0032] The cross fastening portion 20B has a rear end portion connected to the front and rear extending portion 20A, and is inclined so as to be located outside in the vehicle width direction as it goes forward in the vehicle in plan view. Also, as shown in FIG. 2, the cross fastening portion 20B is inclined so as to be located on the lower side of the vehicle from the rear end portion to the front end portion in side view. That is, the cross fastening portion 20B of the rear side frame 20 is inclined so as to be located outside in the vehicle width direction and on the lower side of the vehicle as it goes forward from the rear end portion connected to the front and rear extending portion 20A.

[0033] As shown in FIG. 1, the side fastening portion 20C extends in the vehicle front-rear direction, and the rear end portion of the side fastening portion 20C is connected to the front end portion of the cross fastening portion 20B. Also, as shown in FIG. 2, the side fastening portion 20C is overlapped so as to cover the side portion 14 of the battery frame 12 from above. In this embodiment, as an example, the side fastening portion 20C includes a portion overlapped with the upper surface 14A of the side portion 14 and a portion overlapped with the outer surface in the vehicle width direction of the side portion 14.

[0034] Here, as shown in FIG. 1, the rear side frame 20 is fixed to the battery frame 12 at the first fixing portion P1, the second fixing portion P2, and the third fixing portion P3. The first fixing portion P1 is set at the connection portion between the straight portion 16A and the inclined portion 16B in the battery frame 12. At this first fixing portion P1, the cross portion 16 of the battery frame 12 and the cross fastening portion 20B are mechanically fastened by screwing in the bolt 30 from above the vehicle. Note that a weld nut or the like that engages with the bolt 30 may be provided in the closed cross section of the cross portion 16.

[0035] Note that, as shown in FIG. 3, the first fixing portion P1 of the present embodiment is set below the main body of the cross fastening portion 20B of the rear side frame 20. For this reason, the cross fastening portion 20B and the cross portion 16 are fastened by screwing a bolt 30 into the mounting seat branched from the cross fastening portion 20B. For the sake of convenience of explanation, illustration of the mounting seat is omitted.

[0036] As shown in FIGS. 1 and 2, the second fixing portion P2 is set on the rear end surface 14B of the side portion 14 outside the vehicle width direction with respect to the first fixing portion P1. In the second fixing portion P2, the side fastening portion 20C is overlapped from above the side portion 14, and the rear side frame 20 and the battery frame 12 are fastened by screwing a bolt 32 from the vehicle rear side. Note that a weld nut or the like that engages with the bolt 32 may be provided in the closed cross section of the side portion 14.

[0037] The third fixing portion P3 is set in front of the vehicle with respect to the second fixing portion P2. In the third fixing portion P3, the side fastening portion 20C is overlapped from above the side portion 14, and the rear side frame 20 and the battery frame 12 are fastened by screwing two bolts 34 from above the vehicle of the side fastening portion 20C. Note that a weld nut or the like that engages with the bolt 34 may be provided in the closed cross section of the side portion 14.

[0038] (Function) Next, the function of the vehicle lower structure according to the present embodiment will be described.

[0039] In the vehicle underbody structure according to this embodiment, as shown in FIG. 1, the battery frame 12 is configured to include side portions 14 and a cross portion 16. A pair of left and right side portions 14 are provided and extend in the longitudinal direction of the vehicle respectively. The cross portion 16 extends in the vehicle width direction and connects the rear ends of the side portions 14 to each other. Further, a rear side frame 20 is connected to the battery frame 12. In this way, by connecting the rear side frame 20 to the battery frame 12, the load during a rear collision (rear-end collision) can be transmitted to the battery frame 12, and the battery frame 12 functions as a frame of the vehicle body. That is, it is not necessary to provide a skeleton at the lower part of the vehicle separately from the battery frame 12, and the mounting volume of the battery 100 can be increased.

[0040] Further, a pair of left and right rear side frames 20 are provided, and each includes a first fixing portion P1 fixed to the cross portion 16 of the battery frame 12 and a second fixing portion P2 fixed to the rear end surface 14B of the side portion 14 of the battery frame 12 outside the vehicle width direction with respect to the first fixing portion P1. Thereby, even when a moment acts on the rear side frame 20 during a rear-end collision and a force acts in a direction away from the side portion 14 of the battery frame 12 with respect to the rear side frame 20, the rear side frame 20 is fixed to the rear end surface 14B of the side portion 14 by the second fixing portion P2, so that the fixed state between the rear side frame 20 and the battery frame 12 can be maintained.

[0041] That is, in FIG. 1, when a collision load is input in the direction of arrow L1 in the figure to the rear side frame 20 during a rear-end collision, a moment acting in the direction of arrow L2 in the figure is generated with respect to the side fastening portion 20C. At this time, since the rear side frame 20 is fixed to the rear end surface 14B of the side portion 14 by the second fixing portion P2, the fixed state between the rear side frame 20 and the battery frame 12 can be maintained.

[0042] Further, in the present embodiment, since the inclined portion 16B of the cross portion 16 in the battery frame 12 is inclined so as to be positioned on the vehicle front side as it goes outward in the vehicle width direction in plan view, the collision load at the time of rear impact can be efficiently transmitted to the side portion 14 via the inclined portion 16B. That is, in a structure in which the side portion 14 and the cross portion 16 are connected at substantially a right angle in plan view, the load concentrates on this connection portion. However, in the present embodiment, the concentration of the load can be suppressed, and the load can be easily transmitted from the inclined portion 16B to the side portion 14.

[0043] Furthermore, in the present embodiment, the first fixing portion P1 is provided at the connection portion between the inclined portion 16B and the straight portion 16A. Thereby, the load input from the rear side frame 20 to the battery frame 12 can be transmitted to both the inclined portion 16B and the straight portion 16A. In particular, when a collision load is input from an obliquely rearward direction, the load transmitted from the rear side frame 20 on the collision side to the battery frame 12 can be transmitted to the anti-collision side via the straight portion 16A.

[0044] Furthermore, in the present embodiment, the front end portion of the front-rear extending portion 20A of the rear side frame 20 is connected in the vicinity of the first fixing portion P1. Thereby, the collision load transmitted from the front-rear extending portion 20A can be received by the first fixing portion P1.

[0045] <Second Embodiment> Next, the vehicle lower structure according to the second embodiment will be described with reference to FIG. 4. Note that the same reference numerals are given to the same configurations as those in the first embodiment, and the description will be omitted as appropriate.

[0046] FIG. 4 is a plan view showing a main part of the vehicle lower structure according to the second embodiment. As shown in this FIG. 4, a vehicle 50 to which the vehicle lower structure of the present embodiment is applied includes a battery frame 12 and a front side frame 54. The battery frame 12 is a frame that surrounds the battery 100, and includes a side portion 14 and a cross portion 52.

[0047] The cross member 52 extends in the vehicle width direction and connects the front ends of the side portions 14. Here, the cross member 52 includes a straight portion 52A and an inclined portion 52B. The straight portion 52A is provided at the center in the vehicle width direction of the cross member 52 and extends in the vehicle width direction.

[0048] The inclined portion 52B is provided at both ends in the vehicle width direction of the cross member 52 and is inclined in a plan view so as to be located on the rear side of the vehicle as it goes outward in the vehicle width direction. Specifically, the inclined portion 52B located at the right end of the cross member 52 has its left end connected to the straight portion 52A and is inclined toward the rear side of the vehicle from the left end to the right end. And the right end of this inclined portion 52B is connected to the rear end of the side portion 14.

[0049] On the other hand, the inclined portion 16B located at the left end of the cross member 16 has its right end connected to the straight portion 16A and is inclined toward the rear side of the vehicle from the right end to the left end. And the left end of this inclined portion 16B is connected to the rear end of the side portion 14.

[0050] A pair of left and right front side frames 54 are provided and each extends in the vehicle longitudinal direction. Also, the front end portion of the front side frame 54 is connected to the battery frame 12.

[0051] The front side frame 54 may be formed, for example, by stacking steel plates into a closed cross-section shape, or may be formed by extrusion molding or the like. Also, it may be formed by casting or the like. Further, the front side frame 54 may be connected in the vehicle width direction by a cross member (not shown). In this case, the cross member and the left and right front side frames 54 may be integrally formed.

[0052] Here, each of the pair of left and right front side frames 54 includes a front and rear extending portion 54A, a cross fastening portion 54B, and a side fastening portion 54C. In this embodiment, as an example, the front and rear extending portion 54A, the cross fastening portion 54B, and the side fastening portion 54C are integrally formed.

[0053] The right front and rear extending portion 54A extends in the vehicle front-rear direction, and the rear end portion of the front and rear extending portion 54A is located at the connection portion (boundary portion) between the straight portion 52A and the right inclined portion 52B of the cross portion 52 in the battery frame 12 in plan view. Also, the left front and rear extending portion 54A extends in the vehicle front-rear direction, and the rear end portion of the front and rear extending portion 54A is located at the connection portion (boundary portion) between the straight portion 52A and the left inclined portion 52B of the cross portion 52 in the battery frame 12 in plan view.

[0054] The cross fastening portion 54B has its rear end portion connected to the front and rear extending portion 54A, and is inclined so as to be located on the outer side in the vehicle width direction as it goes toward the rear of the vehicle in plan view. Also, as shown in FIG. 2, the cross fastening portion 54B is inclined so as to be located on the lower side of the vehicle as it goes from the front end portion to the rear end portion in side view. That is, the cross fastening portion 54B of the rear side frame 20 is inclined so as to be located on the outer side in the vehicle width direction and on the lower side of the vehicle as it goes from the front end portion connected to the front and rear extending portion 54A toward the rear side of the vehicle.

[0055] Here, the front side frame 54 is fixed to the battery frame 12 at the fourth fixing portion P4, the fifth fixing portion P5, and the sixth fixing portion P6. The first fixing portion P4 is set at the connection portion between the straight portion 52A and the inclined portion 52B in the battery frame 12. At this first fixing portion P4, the cross portion 52 of the battery frame 12 and the cross fastening portion 54B are mechanically fastened by screwing in a bolt 60 from above the vehicle. Note that a weld nut or the like that engages with the bolt 60 may be provided inside the closed cross section of the cross portion 52.

[0056] The fifth fixing portion P5 is set on the front end surface 14C of the side portion 14 on the outer side in the vehicle width direction than the fourth fixing portion P4. At the fifth fixing portion P5, the front side frame 54 and the battery frame 12 are fastened by screwing in a bolt 62 from the front side of the vehicle with the side fastening portion 54C overlapped from above the side portion 14. Note that a weld nut or the like that engages with the bolt 62 may be provided inside the closed cross section of the side portion 14.

[0057] The sixth fixing portion P6 is set further rearward of the vehicle than the fifth fixing portion P5. At the sixth fixing portion P6, with the side fastening portion 54C superposed from above the side portion 14, two bolts 64 are screwed in from above the vehicle of the side fastening portion 54C, whereby the front side frame 54 and the battery frame 12 are fastened. Note that a weld nut or the like that engages with the bolt 64 may be provided in the closed cross section of the side portion 14.

[0058] (Function) Next, the function of the vehicle lower structure according to the present embodiment will be described.

[0059] In the present embodiment, in FIG. 4, when a collision load is input in the direction of arrow L3 in the figure to the front side frame 54 during a frontal collision, a moment acting in the direction of arrow L4 in the figure is generated with respect to the side fastening portion 54C. At this time, since the front side frame 54 is fixed to the front end face 14C of the side portion 14 at the fifth fixing portion P5, the fixed state of the front side frame 54 and the battery frame 12 can be maintained. Other functions are the same as those in the first embodiment.

[0060] As described above, the vehicle lower structure according to the present invention has been described. Needless to say, the present invention can be implemented in various modes without departing from the gist of the present invention. For example, in the above embodiment, both ends of the cross portion 16 are inclined portions that are inclined so as to be located on the front side of the vehicle as they go outward in the vehicle width direction in plan view, but the present invention is not limited to this. That is, a structure in which the cross portion and the side portion are joined at a substantially right angle may be adopted, but from the viewpoint of suppressing the concentration of the collision load at the corner portion, a structure in which both ends of the cross portion are inclined is preferable.

[0061] In addition, in the above embodiment, the first fixing portion P1 fastens the battery frame 12 and the rear side frame 20 with one bolt 30, but it is not limited thereto, and they may be fastened with a plurality of bolts. Similarly, in the second fixing portion P2 and the third fixing portion P3, the number of bolts is not limited. Further, the battery frame 12 and the rear side frame 20 may be mechanically fastened by a method other than bolts.

Description of Reference Numerals

[0062] 12 Battery frame 14 Side portion 16 Cross portion 16A Straight portion 16B Inclined portion 20 Rear side frame 100 Battery 52 Cross portion 54 Front side frame P1 First fixing portion P2 Second fixing portion P4 Fourth fixing portion P5 Fifth fixing portion

Claims

1. A battery frame configured to surround a battery, including a pair of left and right side portions provided to extend in the longitudinal direction of the vehicle respectively, and a cross portion extending in the vehicle width direction to connect the rear ends of the side portions; A pair of left and right rear side frames provided to extend in the longitudinal direction of the vehicle respectively, with the front end portions thereof connected to the battery frame; having; The rear side frame includes a first fixing portion fixed to the cross portion, and a second fixing portion fixed to the rear end surface of the side portion on the outer side in the vehicle width direction with respect to the first fixing portion. A vehicle underbody structure.

2. The vehicle underbody structure according to Claim 1, wherein both end portions of the cross portion in the vehicle width direction are inclined portions inclined so as to be positioned on the front side of the vehicle as they go outward in the vehicle width direction in plan view.

3. The vehicle underbody structure according to Claim 2, wherein the first fixing portion is provided at a connection portion between a straight portion linearly extending in the vehicle width direction and the inclined portion in the cross portion.

4. The vehicle underbody structure according to Claim 3, wherein the rear side frame extends rearward in the vehicle from the connection portion in plan view.

5. A battery frame configured to surround a battery, including a pair of left and right side portions provided to extend in the longitudinal direction of the vehicle respectively, and a cross portion extending in the vehicle width direction to connect the front ends of the side portions; A pair of left and right front side frames provided to extend in the longitudinal direction of the vehicle respectively, with the rear end portions thereof connected to the battery frame; having; The front side frame includes a fourth fixing portion fixed to the cross portion, and a fifth fixing portion fixed to the front end surface of the side portion on the outer side in the vehicle width direction with respect to the fourth fixing portion. A vehicle underbody structure.

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