JP7331759B2 - electric vehicle undercarriage - Google Patents

Description

The present invention relates to a lower structure of an electric vehicle in which a battery unit is attached under the floor.

Regarding the floor frame under the floor, for example, as disclosed in Patent Document 1 below, there is known a structure in which the portion from the front end to the rear side is inclined outward in the vehicle width direction where the side sills are present and connected to the side sills. ing. The floor frame of Patent Document 1 uses a front seat support cross member, a so-called No. It is connected to the side sill at two cross member positions.

By the way, the floor frame functions to absorb and transmit crash loads. For this reason, if the slope of the floor frame from the front end to the rear side is small, it is advantageous for load transmission, but it is disadvantageous in terms of laying out a wide range of large vehicle parts such as battery units under the floor. On the other hand, if the inclination of the floor frame is too large, the layout property is good, but there is a concern that the load transmission will be insufficient.

JP 2018-184062 A

SUMMARY OF THE INVENTION Accordingly, the main object of the present invention is to improve the layout property of the battery unit and the like under the floor while preventing the deterioration of the load transmission performance.

Means for this purpose are a lower structure of an electric vehicle, which includes a floor, left and right side sills joined to both ends of the floor in the vehicle width direction and extending in the vehicle front-rear direction, and side sills joined below the floor in the vehicle front-rear direction. a front cross member connecting the left and right side sills above the floor ; and a spaced -apart space behind the front cross member above the floor between the floor frames. The floor frame extends obliquely rearward and outward in the vehicle width direction from a position at the front end of the floor and inward in the vehicle width direction from the side sills. After being connected to the side sill between the side cross members, it is formed to extend rearward along the side sill, and the floor frame extends rearward along the side sill rearward from a connection portion where the floor frame connects to the side sill. This is a lower structure of an electric vehicle in which a battery unit is arranged between the extending floor frames.

In this configuration, the portion where the floor frame is connected to the side sill is increased in rigidity by the front cross member and the rear cross member. Therefore, even if the inclination angle of the floor frame is large, it is possible to secure a large installation space for the battery unit while ensuring the load transmission performance.

In one aspect of the present invention, the floor frame includes a lower wall portion and both side wall portions extending upward from both ends of the lower wall portion and having upper ends in contact with the floor. It is preferable that a reinforcing member is disposed on the ridgeline between the wall and the side wall from immediately before to immediately after the connecting portion to the side sill.

In this configuration, the reinforcement member reinforces the vicinity of the connecting portion of the floor frame to the side sill.

In one aspect of the present invention, the side sill has a hollow cross-sectional structure, and joint members are arranged in front of and behind the connection portion of the side sill to which the floor frame is connected to partition the interior of the hollow cross section of the side sill in the front-rear direction. It is preferable to use a set configuration.

In this configuration, the joint member reinforces the side sill, which reinforces the bent connecting portion of the floor frame to the side sill.

In one aspect of the present invention, the passenger seat, the front cross member and the rear cross member are arranged on the floor and attached to the front and rear sides of the passenger seat. A front seat bracket attached across the front cross member portion, to which the front side is attached and the floor frame is arranged below, and the side sill, and a rear side of the passenger seat is attached, and the floor frame is arranged below. and a rear seat bracket mounted across the side sill.

In this configuration, the strength of bonding the front cross member and the rear cross member to the side sills is increased by the front seat bracket and the rear seat bracket, so that the connecting portion of the floor frame to the side sills is reinforced on the side sill side.

In one aspect of the present invention, a high-voltage device may be arranged forwardly and inwardly in the vehicle width direction of a connecting portion of the floor frame to the side sill.

In this configuration, a high-voltage device that is smaller than the battery unit is efficiently arranged while securing the installation space for the battery unit.

According to the present invention, the rigidity of the portion of the floor frame connected to the side sill is increased to increase the inclination angle of the floor frame. The layout property of the battery unit to be arranged can be improved.

1 is a schematic front view of a lower structure of an electric vehicle; FIG. FIG. 2 is a plan view of the lower structure of the electric vehicle; The bottom view of the lower structure of an electric vehicle. FIG. 3 is a cut end view of the portion corresponding to AA of FIG. 2 in the lower structure; FIG. 3 is a cut end view of a portion corresponding to BB in FIG. 2 in the lower structure; FIG. 3 is a cut end view of the portion corresponding to CC in FIG. 2 in the lower structure;

One mode for carrying out the present invention will be described below with reference to the drawings.

FIG. 1 shows a schematic front view of the lower structure of an electric vehicle. This lower structure is a structure that achieves both good layout of the battery unit 12 mounted below the floor 11 and good load transmission in the event of a frontal collision.

The lower structure includes side sills 14, which are frame members having a closed cross section, at both ends in the vehicle width direction of a floor panel 13 that constitutes the floor 11. As shown in FIG. The side sill 14 is composed of an inner member 14a and an outer member 14b and extends in the longitudinal direction of the vehicle. A joint portion 13a at the end of the floor panel 13 is connected to the inner surface of the side sill 14, that is, the upper end portion of the inner member 14a.

The floor panel 13 has a tunnel portion 13b in the center in the width direction of the vehicle, in which drive train components (not shown) are routed. The tunnel portion 13b bulges upward in a generally arch-shaped cross section and extends in the vehicle front-rear direction.

A pair of floor frames 15 are provided on the lower surface of the floor panel 13 and outside in the vehicle width direction. Like the side sills 14, the left and right floor frames 15 are also closed cross-section frame members, in other words, hollow cross-section structures, and extend in the longitudinal direction of the vehicle.

The battery unit 12 is attached from below between the left and right floor frames 15 below the floor 11 .

The battery unit 12 has two battery modules 21 on the left and right sides corresponding to the width direction of the vehicle. there is The battery module 21 also has a lower case 21a and an upper case 21b, which are fixed to each other by fasteners. Note that the left and right battery modules 21 do not necessarily have the same shape or a symmetrical shape. The cases of the illustrated battery modules 21 have different shapes and different lengths in the longitudinal direction of the vehicle. The case of the battery module 21 also accommodates necessary members such as a junction box.

A frame member 16 is provided below the battery unit 12 so as to cover the battery unit 12 .

In the lower structure having the schematic structure as described above, the floor frame 15 extending in the longitudinal direction of the vehicle is partially bent as shown in FIG. 2 which is a plan view of the lower structure and FIG. 3 which is a bottom view of the lower structure. It has a curved shape.

2, illustration of the floor panel 13 is omitted except for the tunnel portion 13b for the sake of convenience. The white arrows in FIGS. 2 and 3 are intended to aid understanding of the drawings, and "Fr" and "Rr" in the arrows represent "front" and "rear" of the vehicle, respectively. Therefore, the direction connecting "Fr" and "Rr" is the longitudinal direction of the vehicle.

That is, the floor frame 15 as a whole does not extend straight in the longitudinal direction of the vehicle, but bends in the middle of the longitudinal direction. The floor frame 15 will be described together with the mounting position to the floor panel 13. The floor frame 15 is located between the tunnel front end, which is the front end of the tunnel portion 13b in the vehicle front-rear direction, and the side sill front end, which is the front end of the side sill 14 in the vehicle front-rear direction. has a starting end at the position of

A floor frame 15 extending rearward from between the tunnel portion 13b and the side sill 14 in the vehicle width direction extends obliquely outward in the vehicle width direction and connects the floor frames 15 (so-called No. 2 cross member). 17 and a rear side cross member (so-called No. 2.5 cross member) 18 are connected to the side sill 14 . The floor frame 15 extends straight rearward along the side sill 14 behind the connecting portion 19 . The connecting portion 19 indicates a portion where the floor frame 15 is connected to the side sill 14, that is, the most forward portion in the vehicle direction of the portion where the side sill 14 and the floor frame 15 are integrated.

The battery unit 12 arranged between the floor frames 15 is mainly arranged behind the connection portion 19 where the floor frame 15 is connected to the side sill 14 between the floor frames 15 . In other words, the main portion of the battery unit 12 is located behind the connecting portion 19 .

The floor frame 15 has a substantially hat-shaped cross section, and has a lower wall portion 15a, both side wall portions, that is, an outer wall 15b, an inner wall 15c, and an upper end piece 15d. The lower wall portion 15 a is a portion that forms the lower surface of the floor frame 15 . The outer wall 15b is a portion that rises on the outer side in the vehicle width direction of the lower wall portion 15a, and the inner wall 15c is a portion that rises on the inner side in the vehicle width direction of the lower wall portion 15a. The upper end piece 15 d extends horizontally and is a portion that is formed at the upper ends of the inner wall 15 c and the outer wall 15 b and is joined to the floor panel 13 .

An upper end piece 15d is also formed at the upper end of the outer wall 15b between the start end of the floor frame 15 and the connecting portion 19, but the portion behind the connecting portion 19 at the upper end of the outer wall 15b is separated from the upper end piece 15d. An extension piece 15e extending upward gradually is formed. Therefore, the outer wall 15b and the extension piece 15e are joined to the inner surface of the side sill 14 behind the connecting portion 19 of the floor frame 15. As shown in FIG.

At the lower ridge of the floor frame 15, as shown in a partially cutaway view on the right side of FIG. 2, and in FIG. As shown, a reinforcing member 51 is disposed immediately before and after the connecting portion 19 to the side sill 14 . That is, the reinforcing member 51 is in surface contact with the inner surface of the floor frame 15 like a patch at the portion spanning the lower wall portion 15a and the outer wall 15b of the floor frame 15 and the portion spanning the lower wall portion 15a and the inner wall 15c. connected in a state. The reinforcement member 51 has a substantially angular plate shape that bends in the same manner as the floor frame 15 bends, and is set to have an appropriate length in the front-rear direction around the connecting portion 19 .

Further, in the hollow section structure side sill 14 to which the floor frame 15 is connected, joint members 52 are arranged before and after the connection portion 19 to which the floor frame 15 is connected. That is, the joint member 52 partitions the inside of the hollow cross-section of the side sill in the front-rear direction, and as shown in the right side sill 14 of FIG. A member 52 is attached over an appropriate range in the vehicle front-rear direction with the connecting portion 19 as the center. The shape of the joint member 52 is appropriately set.

A front cross member 17 and a rear cross member 18 arranged in front and behind the connecting portion 19 indirectly connect the floor frames 15 and the side sills 14 as shown in FIGS. FIG. 5 is a cut end view of a portion corresponding to BB in FIG. 2 in the lower structure, showing the structure of the front cross member 17. FIG. FIG. 6 is a cut end view of the portion corresponding to CC in FIG. 2 in the lower structure, showing the structure of the rear cross member 18. FIG.

Thus, the front cross member 17 and the rear cross member 18 bridge between the side sill 14 and the tunnel portion 13b above the floor panel 13, and connect the floor frame 15 via the tunnel portion 13b. is provided as follows. Both the front cross member 17 and the rear cross member 18 form a closed cross-sectional structure with the floor panel 13 .

The front cross member 17 and the rear cross member 18 are attached to the front and rear of a passenger seat (not shown) arranged on the floor 11, and are spaced apart from each other by a predetermined distance. , seat brackets 55 and 56 are provided.

The seat brackets 55 and 56 include a front seat bracket and a rear seat bracket. The front seat bracket is attached to the front side of the passenger seat, and the front cross member 17 and the side sill 14 are attached to the front side of the passenger seat and below which the floor frame 15 is arranged. It can be attached across the The rear seat bracket is attached across the side sill 14 and the rear cross member 18 where the floor frame 15 is arranged below and to which the rear side of the passenger seat is attached.

Of the seat brackets 55 and 56, the outer bracket 55, which is provided on the outer side in the vehicle width direction, straddles the side sill 14 and the cross member portion where the floor frame 15 is arranged below the front cross member 17 and the rear cross member 18. be provided. 5 and 6, the joint piece 55a on the inner side in the vehicle width direction of the seat bracket 55 is joined to the front cross member 17 or the rear cross member 18, and the joint piece 55b on the outer side in the vehicle width direction is joined to the front cross member 17 or the rear cross member 18. It is joined to the upper surface of the side sill 14 . A portion between the left and right joint pieces 55a and 55b is a support portion 55c to which a sheet is attached, and a nut 57 for fastening is provided inside.

Of the seat brackets 55 and 56, the inner bracket 56 provided on the inner side in the vehicle width direction is fixed to the joint portion of the front cross member 17 and the rear cross member 18 with respect to the tunnel portion 13b, straddling the tunnel portion 13b. That is, the joint piece 56 a on the inner side in the vehicle width direction of the seat bracket 56 is joined to the tunnel portion 13 b , and the joint piece 56 b on the outer side in the vehicle width direction is joined to the front cross member 17 or the rear cross member 18 .

The battery unit 12 arranged below the floor 11 on the vehicle body side of such a structure is attached mainly behind the connecting portion 19 between the floor frames 15 as described above. The attachment of the battery unit 12 to the vehicle body is performed at the portion facing the tunnel portion 13b and the floor frame 15 as shown in FIG.

On the other hand, as shown in FIGS. 2 and 3, a high-voltage device 25 such as an inverter is arranged in front of and inside in the vehicle width direction of the connecting portion 19 of the floor frame 15 to the side sill 14 . Specifically, the high-voltage equipment 25 is provided between the left or right floor frame 15 and the tunnel portion 13b.

In the lower structure configured as described above, compatibility between the layout of the battery unit 12 and the load transferability at the time of a frontal collision is achieved as follows.

That is, around the connection portion 19 where the floor frame 15 is connected to the side sill 14, the rigidity of the highly rigid side sill 14 is further increased by the ring-shaped structure having the front cross member 17 and the rear cross member 18. It is Therefore, even if the front portion of the floor frame 15 extending obliquely outward in the vehicle width direction from the starting end has a large inclination angle, the load transmission performance at the time of a frontal collision can be ensured. In addition, if the front portion of the floor frame 15 has a large inclination angle, a wide space in the vehicle width direction can be obtained behind the connecting portion 19 so as to be long in the vehicle front-rear direction. Therefore, the space for arranging the battery unit 12 can be increased.

In addition, since the reinforcing member 51 is arranged in the lower ridgeline portion of the floor frame 15 and centered on the connection portion 19 , the vicinity of the connection portion 19 to the side sill 14 in the floor frame 15 can be reinforced.

Further, since the joint members 52 are arranged in front of and behind the connection portion 19 of the side sill 14 to which the floor frame 15 is connected, the vicinity of the connection portion 19 from the floor frame 15 of the side sill 14 can be reinforced.

In this way, in addition to the structure in which the floor frame 15 is connected to the portion of the side sill 14 sandwiched between the front cross member 17 and the rear cross member 18, the reinforcement of the floor frame 15 and the side sill 14 respectively provides a frame with higher rigidity. is obtained. Moreover, since the seat bracket 55 is disposed across the front cross member 17 and the rear cross member 18 and the side sill 14, the strength of the connection of the front cross member 17 and the rear cross member 18 to the side sill 14 can be increased. can be done.

Also, the battery unit 12 is mainly arranged behind the connecting portion 19 between the floor frames 15 , while a high-voltage device 25 smaller than the battery unit 12 is arranged in front of the connecting portion 19 . As a result, necessary devices such as the battery unit 12 can be efficiently arranged while securing a large storage space for the battery unit 12 .

DESCRIPTION OF SYMBOLS 11... Floor 12... Battery unit 13b... Tunnel part 14... Side sill 15... Floor frame 17... Front side cross member 18... Rear side cross member 19... Connection part 25... High-voltage apparatus 51... Reinforcement member 52... Joint member 55... Seat bracket

Claims (5)

An electric vehicle undercarriage,
floor and
left and right side sills joined to both ends of the floor in the vehicle width direction and extending in the vehicle front-rear direction;
left and right floor frames that are joined below the floor and extend in the vehicle front-rear direction;
a front cross member that connects the left and right side sills above the floor ;
a rear cross member disposed above the floor behind the front cross member and connecting the floor frames ;
The floor frame extends obliquely rearward and outward in the vehicle width direction from a position at the front end of the floor and on the inner side in the vehicle width direction of the side sill, and the side sill between the front cross member and the rear cross member. formed to extend rearward along the side sill after being connected to the
A battery unit is disposed between the floor frames extending rearward along the side sills, rearward from a connecting portion where the floor frames are connected to the side sills.
Electric vehicle undercarriage. An electric vehicle undercarriage,
floor and
left and right side sills joined to both ends of the floor in the vehicle width direction and extending in the vehicle front-rear direction;
left and right floor frames that are joined below the floor and extend in the vehicle front-rear direction;
a front cross member connecting the left and right side sills;
a rear cross member arranged behind the front cross member with a space therebetween and connecting between the floor frames;
The floor frame extends obliquely rearward and outward in the vehicle width direction from a position at the front end of the floor and on the inner side in the vehicle width direction of the side sill, and the side sill between the front cross member and the rear cross member. formed to extend rearward along the side sill after being connected to the
a battery unit is disposed between the floor frames extending rearward along the side sills behind a connecting portion where the floor frames are connected to the side sills;
The floor frame includes a lower wall portion and both side wall portions that extend upward from both ends of the lower wall portion and whose upper ends are in contact with the floor. A reinforcing member was arranged on the ridge between
Electric vehicle undercarriage. 2. The side sill has a hollow cross-sectional structure, and joint members are disposed in front of and behind the connection portion of the side sill to which the floor frame is connected to partition the interior of the hollow cross-section of the side sill in the front-rear direction. The lower structure of the electric vehicle according to claim 2. a passenger seat;
The front cross member and the rear cross member are arranged on the floor and attached to the front and rear of the passenger seat,
a front seat bracket attached across the side sill and a front cross member portion to which the front side of the passenger seat is attached and where the floor frame is arranged below;
4. Among claims 1 to 3, further comprising: a rear seat bracket mounted across the side sill and a rear cross member portion to which the rear side of the passenger seat is mounted and where the floor frame is arranged below. A substructure for an electric vehicle according to any one of the preceding items. 5. The lower structure of an electric vehicle according to any one of claims 1 to 4, wherein a high-voltage device is disposed forwardly and inwardly in the vehicle width direction of the connecting portion of the floor frame to the side sill.

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