JP2021160511A - Lower structure of electric vehicle - Google Patents

Abstract

To improve layout property of a battery unit or the like below a floor while preventing lowering of load transmission performance at a frontal collision.SOLUTION: In a lower structure of an electric vehicle mounted with a battery unit 12 below a floor 11, floor frames 15 supporting load transmission are extended obliquely backward from a position between a front end of a tunnel part 13b and a front end of a side sill 14 in a vehicle width direction toward the outside in a vehicle width direction, and are connected to the side sill 14 between a front side cross member 17 and a rear side cross member 18 connecting between the floor frames 15. The floor frames 15 are extended backward from a connection part 19 therebetween along the side sill 14. The battery unit 12 is mounted mainly on a part behind the connection part 19 between the floor frames 15.SELECTED DRAWING: Figure 2

Description

The present invention relates to a substructure of an electric vehicle in which a battery unit is mounted below the floor.

As for the floor frame under the floor, for example, as disclosed in Patent Document 1 below, a structure is known in which a portion from the front end to the rear side is inclined outward in the vehicle width direction in which the side sill exists and is connected to the side sill. ing. The floor frame of Patent Document 1 is a front seat support cross member, so-called No. 2 Connected to the side sill at the cross member position.

By the way, the floor frame functions to absorb and transmit the impact load. Therefore, if the inclination of the portion from the front end to the rear side of the floor frame is small, it is advantageous for load transmission, but it is disadvantageous in that a large vehicle part such as a battery unit is widely laid out under the floor. On the other hand, if the inclination of the floor frame is too large, the layout is good, but there is a concern that the load transmission will be insufficient.

Japanese Unexamined Patent Publication No. 2018-184062

Therefore, it is a main object of the present invention to improve the layout of the battery unit or the like under the floor while preventing the load transmission performance from being deteriorated.

The means for this is the lower structure of the 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 front-rear direction of the vehicle, and a front cross member connecting the left and right side sills. From a position on the front end of the floor and inside in the vehicle width direction from the side sill, which is joined to the rear cross member which is arranged at a space behind the front cross member and connects the floor frames to the lower side of the floor. A floor frame extending rearward and diagonally outward in the vehicle width direction, connected to the side sill between the front cross member and the rear cross member, and then extending rearward along the side sill, and the side sill. It is a substructure of an electric vehicle including a battery unit arranged between the floor frames extending rearward along the floor frame.

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 tilt angle of the floor frame is large, the space for arranging the battery unit can be large 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 abutting against the floor, and the lower portion of the floor frame. It is preferable that the reinforcing member is arranged on the ridge line portion between the wall portion and the both side wall portions from immediately before to immediately after the connection portion to the side sill.

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

In one aspect of the present invention, the side sill is a hollow cross-section structure, and knot members for partitioning the inside of the hollow cross section of the side sill in the front-rear direction are arranged before and after the portion of the side sill to which the floor frame is connected. It is good to have a different configuration.

In this configuration, the knot members reinforce the side sill, which reinforces the bent connection of the floor frame to the side sill.

In one aspect of the present invention, the occupant seat, the front cross member, and the rear cross member are arranged on the floor and the front and rear of the occupant seat are attached to the front and rear of the occupant seat. The front seat bracket, which is attached across the front cross member portion and the side sill where the front side is attached and the floor frame is arranged below, and the rear side of the occupant seat are attached and the floor frame is arranged below. It is preferable that the rear seat bracket is provided so as to straddle the rear cross member portion and the side sill.

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

In one aspect of the present invention, it is preferable that the high voltage device is arranged in front of the connection portion of the floor frame to the side sill and inside in the vehicle width direction.

In this configuration, high-voltage equipment smaller than the battery unit is efficiently arranged while securing the arrangement space of the battery unit.

According to the present invention, since the rigidity of the portion connected to the side sill of the floor frame can be increased to increase the inclination angle of the floor frame, the load transmission performance is suppressed from being deteriorated between the floor frames under the floor. The layout of the battery unit to be arranged can be improved.

Schematic front view of the substructure of an electric vehicle. Top view of the substructure of the electric vehicle. Bottom view of the undercarriage of an electric vehicle. The cut end view of the portion corresponding to AA of FIG. 2 in the lower structure. The cut end view of the portion corresponding to BB of FIG. 2 in the lower structure. The cut end view of the portion corresponding to CC of FIG. 2 in the lower structure.

An embodiment 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 the electric vehicle. This lower structure is a structure that achieves both the layout of the battery unit 12 mounted below the floor 11 and the load transmissibility at the time of a head-on collision.

The lower structure includes side sills 14 which are skeleton members having a closed cross section at both ends of the floor panel 13 constituting the floor 11 in the vehicle width direction. The side sill 14 is composed of an inner member 14a and an outer member 14b, and extends in the front-rear direction of the vehicle. The joint portion 13a at the end of the floor panel 13 is connected to the inner side 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 vehicle width direction in which drive system components (not shown) are arranged. The tunnel portion 13b bulges upward in a substantially arched cross section and extends in the front-rear direction of the vehicle.

A pair of floor frames 15 are provided on the lower surface of the floor panel 13 and on the outer side in the vehicle width direction. Like the side sill 14, the left and right floor frames 15 are skeletal members with a closed cross section, in other words, a hollow cross section structure, which extends in the front-rear 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 corresponding to the vehicle width direction, and these left and right battery modules 21 are connected by a connecting portion 22 at the rear portion corresponding to the rear of the vehicle to be integrated. There is. Further, the battery module 21 has a lower case 21a and an upper case 21b, which are fixed to each other by fasteners. The left and right battery modules 21 are not necessarily the same shape or symmetrical shape. The cases of the battery modules 21 in the illustrated example have different shapes and different lengths in the front-rear direction of the vehicle. Necessary members such as a junction box are also housed in the case of the battery module 21.

Below the battery unit 12, a frame member 16 is provided so as to cover the battery unit 12.

In the lower structure having the above-mentioned schematic structure, the floor frame 15 extending in the front-rear 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 bent shape.

In FIG. 2, the floor panel 13 is not shown except for the tunnel portion 13b for convenience. The white arrows in FIGS. 2 and 3 are for the purpose of assisting the 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 front-rear direction of the vehicle.

That is, the entire floor frame 15 does not extend straight in the front-rear direction of the vehicle, but bends in the middle of the longitudinal direction. Explaining the floor frame 15 together with the mounting position with respect to the floor panel 13, the floor frame 15 is between the front end of the tunnel, which is the front end of the tunnel portion 13b in the vehicle width direction in the vehicle front-rear direction, and the front end of the side sill, which is the front end of the side sill 14 in the vehicle front-rear direction. It has a starting point at the position of.

The floor frame 15 extending rearward from between the tunnel portion 13b and the side sill 14 in the vehicle width direction extends diagonally toward the outside in the vehicle width direction, and is a front cross member (so-called No. 2 cross member) connecting the floor frames 15. It is connected to the side sill 14 between the 17 and the rear cross member (so-called No. 2.5 cross member) 18. Behind the connection 19, the floor frame 15 extends straight back along the side sill 14. The connecting portion 19 refers to a portion where the floor frame 15 is connected to the side sill 14, that is, a portion in which the side sill 14 and the floor frame 15 are integrated, which is the most front portion in the vehicle direction.

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

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

From the start end of the floor frame 15 to the connection portion 19, the upper end piece 15d is also formed at the upper end of the outer wall 15b, but the portion rearward from the connection portion 19 at the upper end of the outer wall 15b is from the upper end piece 15d. Gradually, an extending piece 15e extending upward is formed. Therefore, behind the connecting portion 19 of the floor frame 15, the outer wall 15b and the extension piece 15e are joined to the inner side surface of the side sill 14.

On the lower ridgeline portion of the floor frame 15, as shown by breaking a part on the right side of FIG. 2, and in FIG. 4, which is a cut end view of a portion corresponding to AA of FIG. 2 in the lower structure. As shown, the reinforcing member 51 is arranged from immediately before to immediately after the connecting portion 19 to the side sill 14. That is, the reinforcing member 51 comes into surface contact with the inner surface of the floor frame 15 like a patch cloth at the portion straddling the lower wall portion 15a and the outer wall portion 15b of the floor frame 15 and the portion straddling the lower wall portion 15a and the inner wall surface 15c. It is joined in a state. The reinforcing member 51 has a substantially angled shape and has a plate shape that bends in the same manner as the bending of the floor frame 15, and is set to an appropriate length in the front-rear direction around the connecting portion 19.

Further, in the hollow cross-section structure side sill 14 to which the floor frame 15 is connected, knot members 52 are arranged before and after the connecting portion 19 to which the floor frame 15 is connected. That is, the knot member 52 partitions the inside of the hollow cross section of the side sill in the front-rear direction, and as shown by omitting the outer member 14b for the side sill 14 on the right side of FIG. 2, a plurality of knots mounted in the side sill 14. The member 52 is attached around the connecting portion 19 over an appropriate range in the front-rear direction of the vehicle. The shape of the knot member 52 is appropriately set.

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

In this way, the front cross member 17 and the rear cross member 18 are bridged between the side sill 14 and the tunnel portion 13b above the floor panel 13, and the floor frames 15 are connected via the tunnel portion 13b. It 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 the occupant seat (not shown) arranged on the floor 11, and are arranged at predetermined intervals for that purpose. , 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 has a front cross member 17 portion and a side sill 14 to which the front side of the passenger seat is attached and the floor frame 15 is arranged below. It is installed across and. The rear seat bracket is attached so as to straddle the rear cross member 18 portion where the floor frame 15 is arranged below the rear side of the occupant seat and the side sill 14.

Of the seat brackets 55 and 56, the outer bracket 55 which can be provided on the outer side in the vehicle width direction straddles the cross member portion where the floor frame 15 is arranged below the front cross member 17 and the rear cross member 18 and the side sill 14. It will be provided. That is, as shown in FIGS. 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. It is joined to the upper surface of the side sill 14. The portion between the left and right joint pieces 55a and 55b is a support portion 55c to which the seat 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 between the front cross member 17 and the rear cross member 18 with respect to the tunnel portion 13b so as to straddle the tunnel portion 13b. That is, the joint piece 56a on the inner side in the vehicle width direction of the seat bracket 56 is joined to the tunnel portion 13b, and the joint piece 56b 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 having such a structure is mounted mainly behind the connecting portion 19 between the floor frames 15 as described above. The battery unit 12 is attached to the vehicle body side at a 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 the connection portion 19 of the floor frame 15 to the side sill 14 and inside in the vehicle width direction. Specifically, the high-voltage device 25 is provided between either the left or right floor frame 15 and the tunnel portion 13b.

In the substructure configured as described above, the layout of the battery unit 12 and the load transmissibility at the time of a head-on collision can be achieved at the same time as follows.

That is, around the connecting portion 19 in which 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 annular structure having the front cross member 17 and the rear cross member 18. Has been Therefore, even if the inclination angle of the front side portion of the floor frame 15 extending diagonally from the start end to the outside in the vehicle width direction is large, the load transmission performance at the time of a head-on collision can be ensured. Moreover, if the inclination angle of the front side portion of the floor frame 15 is large, a wide space behind the connecting portion 19 in the vehicle width direction can be obtained longer in the vehicle front-rear direction. Therefore, the arrangement space of the battery unit 12 can be increased.

Moreover, since the reinforcing member 51 is arranged in the lower ridge line portion of the floor frame 15 centering on the connecting portion 19, the vicinity of the connecting portion 19 to the side sill 14 in the floor frame 15 can be reinforced.

Further, since the knot members 52 are arranged before and after the connecting portion 19 to which the floor frame 15 of the side sill 14 is connected, the vicinity of the connecting 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, a skeleton having higher rigidity is provided by reinforcing the floor frame 15 and the side sill 14. Is obtained. Further, since the seat bracket 55 is arranged so as to straddle the front cross member 17, the rear cross member 18, and the side sill 14, the bonding strength between the front cross member 17 and the rear cross member 18 to the side sill 14 is increased. Can be done.

Further, the battery unit 12 is mainly arranged behind the connection 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 connection portion 19. As a result, necessary equipment such as the battery unit 12 can be efficiently arranged while taking a large accommodation space for the battery unit 12.

11 ... Floor 12 ... Battery unit 13b ... Tunnel 14 ... Side sill 15 ... Floor frame 17 ... Front cross member 18 ... Rear cross member 19 ... Connection 25 ... High voltage equipment 51 ... Reinforcing member 52 ... Section member 55 ... Seat bracket

Claims (5)

It is the substructure of an electric vehicle and
On the floor
The left and right side sills that are joined to both ends of the floor in the vehicle width direction and extend in the front-rear direction of the vehicle,
With the front cross member that connects the left and right side sills,
A rear cross member that is spaced behind the front cross member and connects the floor frames, and a rear cross member.
It is joined to the lower part of the floor and extends diagonally from the position inside the side sill in the vehicle width direction to the rear and the outside in the vehicle width direction at the front end of the floor, and between the front cross member and the rear cross member. After being connected to the side sill, a floor frame extending rearward along the side sill,
A substructure of an electric vehicle comprising a battery unit disposed between the floor frames extending rearward along the side sill. 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 abutting against the floor, and the lower wall portion and the both side wall portions in the floor frame. The lower structure of the electric vehicle according to claim 1, wherein a reinforcing member is provided on the ridge line portion between the two from immediately before to immediately after the connection portion to the side sill. 2. Substructure of the electric vehicle described in. Seats for passengers and
The front cross member and the rear cross member are arranged on the floor and the front and rear of the occupant seat are attached to the front and rear.
A front seat bracket to which the front side of the occupant seat is attached and the front cross member portion where the floor frame is arranged below and the side sill are attached.
Of claims 1 to 3, a rear cross member portion to which the rear side of the passenger seat is attached and the floor frame is arranged below and a rear seat bracket attached straddling the side sill. Substructure of the electric vehicle according to any one item. The substructure of an electric vehicle according to any one of claims 1 to 4, wherein a high voltage device is arranged in front of the connection portion of the floor frame to the side sill and inside in the vehicle width direction.

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