JP7331758B2 - electric vehicle undercarriage - Google Patents

Description

The present invention relates to a lower structure of an electric vehicle such as a plug-in hybrid vehicle, in which a battery unit is attached under the floor.

As the structure described above, as disclosed in Patent Document 1 below, an upper cross member and a lower cross member are provided between the left and right floor frames under the floor, and the battery unit is sandwiched between them. I have something to install. A battery unit is secured to both the upper cross member and the lower cross member.

In this configuration, the impact load input to the floor frame during a side impact is transferred to the upper and lower cross members to reduce the individual load transfer burden of those cross members.

However, a large load is likely to be applied to the lower cross member on which the battery unit is mounted. In particular, a force acts on the central portion of the lower cross member in the longitudinal direction to bend the lower cross member in a downward convex manner with this portion as a bending point. If the cross member breaks in the center, the battery unit will be damaged, so we want to ensure the rigidity of the cross member. A new problem arises in that the accommodation space becomes narrower.

Japanese Patent No. 5654039

SUMMARY OF THE INVENTION Accordingly, the main object of the present invention is to protect a battery unit without causing inconvenience such as an increase in the weight of the vehicle body.

A means for achieving this is a lower structure of an electric vehicle in which a battery unit is mounted below a floor, and the battery module of the battery unit bulges upward in a substantially arch-shaped cross section at the center of the floor in the vehicle width direction. The battery modules are arranged on the left and right sides of a tunnel portion that extends in the longitudinal direction of the vehicle. A tunnel reinforcement that reinforces the tunnel portion between the fastening portions is provided between the fastening portions, and a reinforcing member fastened to the tunnel portion across the fastening portions with a gap from the tunnel reinforcement. It is a lower structure of an electric vehicle.

In this configuration, the battery unit is fixed to the tunnel portion of the floor, and the central portion of the battery unit is suppressed from being displaced downwardly in a side collision. Moreover, the tunnel reinforcement and the reinforcing member form a ring structure between the tunnel portion side portions of the left and right battery modules fastened to the tunnel portion. Therefore, the mounting rigidity of the battery module to the tunnel portion is high.

In one aspect of the present invention, the reinforcing member may be configured to extend in the vehicle front-rear direction along the arrangement position of the battery unit.

In this configuration, the reinforcing member that is long in the longitudinal direction of the vehicle effectively improves the rigidity of attachment to the tunnel portion.

When the reinforcing member extends in the front-rear direction, the battery module is fixed to the tunnel portion by a plurality of the fastening portions arranged in the front-rear direction of the vehicle, and the reinforcing member is positioned between the plurality of fastening portions. It is good also as a structure extended across.

In this configuration, since the reinforcing member extends in the longitudinal direction of the vehicle together with the portion to which the battery module is fastened, the mounting rigidity to the tunnel portion is further improved.

According to the present invention, by using the tunnel portion, the central portion of the battery unit is prevented from being displaced downwardly in the event of a side collision. It can protect the battery unit. Moreover, since the tunnel portion has a ring-like structure formed by the tunnel reinforcement and the reinforcing member, the mounting rigidity to the floor can be increased, and the effect of battery protection can be further ensured.

1 is a schematic front view of a lower structure of an electric vehicle; FIG. FIG. 2 is a schematic front view showing a separated state of the lower structure of the electric vehicle; FIG. 4 is a plan view of a state in which the battery unit is superimposed on the frame member; 4 is a perspective view of a frame member; FIG. AA sectional view and BB sectional view of FIG. FIG. 4 is a cut end view of a portion corresponding to CD of FIG. 3 in the lower structure; FIG. 4 is a cut end view of the portion corresponding to EF of FIG. 3 in the lower structure; The perspective view which looked up at the tunnel part from the downward direction. FIG. 4 is a perspective view of a state in which the battery unit is fixed to the frame member;

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 effectively improves the mounting rigidity with respect to the floor 11 of the battery unit 12 mounted below the floor 11 .

As shown in FIG. 2, which is a schematic front view showing the separated state of the lower structure, the lower structure includes side sills 14, which are frame members with a closed cross section, at both ends in the vehicle width direction of a floor panel 13 that constitutes a floor 11. there is The side sill 14 extends in the longitudinal direction of the vehicle, and has a joint portion 13a at the end of the floor panel 13 connected to the upper end portion of the inner side surface.

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 on the outer side in the vehicle width direction (outer side of the vehicle). Like the side sills 14, the left and right floor frames 15 are also frame members with closed cross sections and extend in the longitudinal direction of the vehicle. The formation position of the floor frame 15 with respect to the floor panel 13 is appropriately set, but the portion where the battery unit 12 is provided is set on the outermost side in the vehicle width direction, and the outer surface of the floor frame 15 in the vehicle width direction is positioned on the side sill 14 . Bonded to the inner surface. In other words, the floor frame 15 is arranged under both vehicle width direction end portions of the floor panel 13 coupled to the side sill 14 and coupled to the inner surface of the side sill 14 together with the floor panel 13 .

The battery unit 12 is attached from below so as to be arranged between the left and right floor frames 15 below the floor 11 having the general structure as described above.

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 illustrated battery modules 21 have different shapes and different lengths in the longitudinal direction of the vehicle.

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

The frame member 16 has left and right vertical frames 61 extending in the front-rear direction on the vehicle outer side of the battery unit 12 and horizontal frames 62 connecting the left and right vertical frames 61 to each other.

FIG. 3 shows a state in which the battery unit 12 is stacked on the frame member 16. As shown in FIG. 4 is a perspective view of the frame member 16. FIG. The white arrows in FIGS. 3 and 4 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. The same applies to other figures.

As shown in these figures, the vertical frame 61 of the frame member 16 has a closed cross section with a rectangular cross section, and is constructed by connecting both end edges of an outer member 61a and an inner member 61b. The length of the vertical frame 61 is set equal to or slightly longer than the length of the battery unit 12 in the longitudinal direction of the vehicle.

The arrangement interval of the left and right vertical frames 61 is the same as or slightly longer than the length of the battery unit 12 in the vehicle width direction, as shown in FIG. In other words, the left and right vertical frames 61 are arranged at intervals that allow the battery units 12 to be accommodated. In other words, the boundary distance between the battery unit 12 attached so as to be disposed between the floor frames 15 and the vertical frame 61 of the frame member 16 provided so as to cover the battery unit 12 is approximately the floor frame 15 is set to correspond to the interval of

The horizontal frames 62 are rod-shaped rather than plate-shaped with widened surfaces, and are provided in plurality with a gap in the front-rear direction corresponding to the vehicle front-rear direction. Since the left and right vertical frames 61 are connected by a plurality of horizontal frames 62, the frame member 16 has a frame shape.

In this example, there are three horizontal frames 62, namely a front horizontal frame 62a, an intermediate horizontal frame 62b, and a rear horizontal frame 62c from the front side in the vehicle longitudinal direction. The front lateral frame 62a and the rear lateral frame 62c are formed in a straight line, and the intermediate lateral frame 62b is formed in an X shape in plan view with both longitudinal sides bifurcated.

Each horizontal frame 62 has a lower member 63 and an upper member 64 that are integrally connected to each other as shown in FIG. 5(a), which is a sectional view taken along line AA of FIG. The lower member 63 and the upper member 64 are joined to each other at the edge 62d, and a space 62e is formed between the edge 62d to separate the lower member 63 and the upper member 64. Each horizontal frame 62 is It has a closed cross-sectional structure.

Among the horizontal frames 62, each of the horizontal frames 62 has a portion facing the center of the battery module 21 in the longitudinal direction corresponding to the center in the vehicle width direction. A hole 65 is formed. That is, in the case of the battery module 21 of the illustrated example, the two battery modules 21 are installed in the middle portion in the longitudinal direction of the intermediate horizontal frame 62b and the rear horizontal frame 62c, which corresponds to the center of the battery module 21 in the vehicle width direction. Through holes 65 are arranged side by side.

The through hole 65 is formed in a bulging portion 66 formed by projecting both the upper member 64 and the lower member 63 upward. The bulging portion 66 is circular in plan view, and has a recess 67 below which the head of the bolt is accommodated (see FIG. 6).

Each horizontal frame 62 has upright portions 71 extending upward at both ends in the longitudinal direction. The standing portion 71 is a portion that is fixed to the inner surface of the vertical frame 61 and is a mounting portion that is used for fixing to the vehicle body side, specifically to the floor frame 15 . The height of the standing portion 71 is substantially the same as the height of the vertical frame 61 .

The standing portion 71 is configured as shown in FIG. 5B, which is a cross-sectional view taken along line BB of FIG. That is, both ends of the lower member 63 have upright pieces 72 that stand upright. Raised bottom portions 73 positioned above the lower surface of the lower member 63 are formed at portions corresponding to the widthwise centers of the upright pieces 72 at both ends of the lower member 63 . A mounting weld nut 74 is provided on the raised bottom portion 73 . The attachment weld nut 74 extends from the lower end of the frame member 16 to the floor frame 15, and has a screw hole 74a directed vertically. The height of the upper end face of the mounting weld nut 74 is higher than the upper end position of the standing piece 72 .

The upper member 64 has coating portions 75 formed at both ends in the longitudinal direction thereof to enclose the mounting weld nut 74. The coating portion 75 includes a pair of inclined surfaces 75a positioned to sandwich the mounting weld nut 74 and the mounting weld nut 74. It has a vertical surface 75b positioned along the .

The outer end of the lateral frame 62 having such a standing portion 71 extends upward to the height of the floor frame 15 so as to embrace the mounting weld nut 74 .

Through-holes 72a are formed at two positions sandwiching the mounting weld nut 74 in the upright piece 72 of the lower member 63 or at one position adjacent to the mounting weld nut 74. A nut 76 is welded on. The through hole 72 a and the nut 76 are structures for coupling to the vertical frame 61 .

That is, through holes 61c and 61d through which the bolts 77 can be inserted are formed in the vertical frame 61 corresponding to positions where the three horizontal frames 62 are fixed. Bolts are inserted into the through holes 61c and 61d from the outer surface of the vertical frame 61, and the tips of the bolts 77 are screwed into the nuts 76 on the inner surfaces of the standing pieces 72, thereby connecting the vertical frame 61 and the horizontal frame 62. , the frame member 16 is constructed.

When connecting the vertical frame 61 and the horizontal frame 62, the lower end position of the vertical frame 61 and the lower end position of the horizontal frame 62 are aligned at the same height. Since the horizontal frame 62 has the standing portions 71 at both ends and is joined to the vertical frame 61 with the height of the lower end aligned, the horizontal frame 62 is arranged near the bottom of the vertical frame 61 .

Also, the upper end of the mounting weld nut 74 , which is higher than the upper end position of the standing piece 72 , is positioned above the upper surface of the vertical frame 61 .

A recess 61e for accommodating the head of the bolt 77 is formed in a portion of the outer member 61a of the vertical frame 61 where the through hole 61c through which the bolt 77 is inserted is formed.

Also, an undercover 78 is provided on the lower surface of the frame member 16 . The undercover 78 has a plate shape and covers between the front lateral frame 62a and the intermediate lateral frame 62b and between the intermediate lateral frame 62b and the rear lateral frame 62c. An opening 79 that is not covered with an undercover is provided between the branched portions at both ends of the intermediate horizontal frame 62b.

The fixing of the undercover 78 is performed by welding or the like to the lower surface of the edge 62d of each horizontal frame 62 as shown in FIG. 5(a).

7, the battery unit 12 is configured such that the tunnel portion side portion of the battery module 21 is the general surface of the floor 11 in the tunnel portion 13b, that is, the main surface of the floor 11. As shown in FIG. It is fastened to the higher right and left fastening portions 13c (both sides in the vehicle width direction). FIG. 7 is a cut end view of the portion corresponding to EF of FIG. 3 in the lower structure.

The fastening portion 13c is composed of a fixing portion forming member 81 provided on the ceiling surface of the tunnel portion 13b. The fixed portion forming member 81 is formed at the upper end portion of the tunnel portion 13b inside the outer end of the tunnel portion 13b of the floor panel 13 . The fixed portion forming member 81 has a substantially triangular shape when viewed from the longitudinal direction of the tunnel portion 13b, and is coupled to upper corners of the inner surface of the tunnel portion 13b.

As shown in FIG. 8, which is a perspective view looking up obliquely from below, the fixing portion forming member 81 has a horizontal surface 81a and an upright surface 81b that stands upright inside the horizontal surface 81a, and has a through hole 81c in the horizontal surface 81a. are doing. A nut 82 is held inside the fixing portion forming member 81 and above the through hole 81c. The fixed portion forming member 81 is provided at two locations with a gap therebetween in the vehicle front-rear direction.

In the vicinity of the fastening portion 13c (fixing portion forming member 81), a tunnel reinforcement 91 provided between the left and right fastening portions 13c and a tunnel reinforcement 91 straddling the fastening portion 13c are arranged vertically. A reinforcing member 92 is provided which is fastened to the tunnel portion 13b with an opening.

The tunnel reinforcement 91 reinforces the tunnel portion 13b between the fastening portions 13c, and is formed in a shape along the inner surface of the upper end portion of the tunnel portion 13b as shown in FIG. That is, it has a ceiling surface portion 91a corresponding to the ceiling surface of the tunnel portion 13b and side surface portions 91b extending downward from both left and right sides of the ceiling surface portion 91a. The ceiling surface portion 91a and the side surface portion 91b are formed to have an appropriate width in the longitudinal direction of the tunnel portion 13b, and a bulging rib 91c connecting the side surface portions 91b on both left and right sides and the ceiling surface portion 91a is formed in the intermediate portion in the width direction. ing.

The fixed portion forming member 81 described above is coupled to the lower surface of the tunnel reinforcement 91 .

As shown in FIG. 9, the reinforcing member 92 has right and left pinched pieces 92a coupled to the fastening portion 13c, and a plate-shaped main body portion 92b connecting these pieces. The reinforcing member 92 extends in the front-rear direction along the position where the battery unit 12 is disposed. is formed so as to straddle between two front and rear fastening portions 13c.

A body portion 92b of the reinforcing member 92 is formed with a bulging rib 92c extending along the vehicle front-rear direction.

The bending of the reinforcing member 92 in the longitudinal direction corresponds to the change in height of the tunnel portion 13b.

The battery unit 12 may be fixed directly to the floor 11 for fixing the battery unit 12 to the tunnel portion 13b.

As shown in FIG. 9 , the bracket 83 is fixed to the tunnel portion 13b side portion of the battery module 21 and extends upward from the upper surface of the battery module 21 .

Since the pair of left and right fastening portions 13c are provided at two front and rear locations, the pair of left and right brackets 83 are fixed to the front and rear in accordance with the spacing between the fastening portions 13c.

The two sets of four brackets 83 have the same structure. The bracket 83 is formed by pressing a metal plate, and has two horizontal support plates 83a at its lower end with a gap in the direction corresponding to the longitudinal direction of the vehicle. A through hole is formed in the center of the support plate 83a. The spacing of the through holes is the same as the spacing of the through holes 27 a formed in the support portion 27 of the battery module 21 .

A vertical piece 83b that rises upward and is united extends from the end of the two support plates 83a on the side corresponding to the outer side in the vehicle width direction. An inclined piece 83c that is inclined forward is also provided. An upper end piece 83d extending horizontally in a direction corresponding to the inner side in the vehicle width direction extends from the upper end of the inclined piece 83c. The upper end piece 83d is a portion in contact with the horizontal surface 81a of the fixing portion forming member 81, and has a through hole 83e in the center.

In order to fix the battery unit 12 to the tunnel portion 13b of the floor panel 13, the bracket 83 is fixed to the upper surface of the support portion 27 of the battery module 21 in advance. The bracket 83 is fixed by passing the bolt 84 through the through hole of the support plate 83 a from above, inserting the bolt 84 through the through hole 27 a of the support portion 27 , and screwing the tip of the bolt 84 into the nut 28 .

In the battery unit 12 to which the bracket 83 is fixed, the upper end piece 83d of the bracket 83 is brought into contact with the lower surface of the horizontal surface 81a of the fixing portion forming member 81 with the sandwiched piece 92a of the reinforcing member 92 interposed therebetween. In this state, when the bolt 85 is inserted from below the upper end piece 83d and screwed into the nut 82, the battery unit 12 is fixed to the tunnel portion 13b, and the reinforcing member 92 is held below the ceiling surface of the tunnel portion 13b. be done.

As a result, an annular structure including the fastening portion 13c is formed by coupling the tunnel reinforcement 91 along the ceiling surface of the tunnel portion 13b and the reinforcing member 92, which is spaced below the tunnel reinforcement 91 and extends in the left-right direction. be done.

The battery unit 12 whose vehicle width direction central portion is fixed to the tunnel portion 13b as described above is also fixed to the floor 11 at its vehicle width direction outer portion. This fixation is made to the floor frame 15 in the same manner as the fixation of the frame member 16 .

FIG. 6 shows a structure for attaching the frame member 16 to the floor frame 15. As shown in FIG. FIG. 6 is a cut end view of the portion corresponding to CD in FIG. 3 in the lower structure, showing the fixing structure of the frame member 16 to the battery unit 12 together with the fixing structure of the frame member 16 to the floor frame 15. .

That is, a cup-shaped fixing portion forming member 86 is provided at the mounting position of the frame member 16 on the lower surface of the floor frame 15 . The fixing portion forming member 86 has an inner coupling piece 86a coupled to the inner surface of the floor frame 15 on the inner side in the vehicle width direction, and a horizontal connecting piece 86a coupled to the lower surface of the floor frame 15 on the outer side in the vehicle width direction. It has an outer coupling piece 86b. A portion of the fixed portion forming member 86 corresponding to the vehicle front-rear direction has an inclined portion (not shown) extending upward in the vehicle front-rear direction. (not shown) are formed.

A required number of through-holes are formed in the lower surface 86 c of the fixing portion forming member 86 , and nuts 87 are held above the through holes inside the fixing portion forming member 86 . The nut 87 is formed to a required length and penetrates the floor frame 15 .

Since the frame members 16 fixed to the floor frame 15 and the battery units 12 are fixed at different positions in the front-rear direction, for example, the required number is two in the portion where the fixed positions are close, and in the portion apart. Then it becomes one.

The fixing portion forming member 86 has a cup-shaped portion including a lower surface that holds the nut 87 and a pair of inclined portions as one mountain, and is spaced between the standing portions 71 of the frame member 16 and the mounting position of the battery unit 12 . It has one mountain or multiple mountains depending on the situation.

In order to fix the frame member 16 to the floor frame 15, a bolt 88 is screwed from below into the mounting weld nut 74 of the erected portion 71 of the frame member 16, and then the tip of the bolt 88 is attached to the fixed portion forming member. The nut 87 of 86 is screwed. As a result, the upper end surface of the mounting weld nut 74 is pressed against the lower surface 85c of the fixing portion forming member 86. As shown in FIG.

Since the battery unit 12 is fixed to the floor frame 15 on the outside in the vehicle width direction in the same manner as the frame member 16 is fixed to the floor frame 15, a detailed description thereof will be omitted.

The center of the lateral frame 62 in the frame member 16 in the vehicle width direction is fixed to the battery unit 12 as shown in FIG. As a result, the center of the lateral frame 62 in the vehicle width direction is attached to the tunnel portion 13b.

Specifically, the lateral frame 62 is fixed to the battery unit 12 by inserting bolts 89 through the through holes 65 of the intermediate lateral frame 62b and the rear lateral frame 62c. A vehicle-interior holding portion 23 is protrudingly provided at a portion corresponding to the through hole 65 of the lateral frame 62 of the vehicle width direction inner side surfaces of the lower case 21 a and the upper case 21 b of the battery module 21 . The portion 23 is formed with a through hole 23a through which the bolt 89 is passed. Upper case 21b holds nut 24 above through hole 23a.

For fixing, a bolt 89 inserted from below into the through hole 65 of the lateral frame 62 is inserted through the through hole 23a of the vehicle interior holding portion 23 of the battery module 21 and screwed onto the nut 24 on the upper surface. In FIG. 6, 25 is a cylindrical spacer.

In the lower structure configured as described above, the battery unit 12 is fastened to the tunnel portion 13b of the floor 11, so that the central portion of the battery unit 12 is prevented from being displaced in a convex downward direction in the event of a side collision. be. Moreover, an annular structure including the tunnel reinforcement 91 and the reinforcing member 92 is formed in the portion of the tunnel portion 13b having the fastening portion 13c of the battery unit 12 . Therefore, the mounting rigidity of the battery unit 12 to the tunnel portion 13b is high.

Moreover, the size of the tunnel reinforcement 91 and the reinforcing member 92 can be relatively small and lightweight compared to the case where the plate thickness of the member receiving the transmission of the collision load is increased or the cross section is increased.

In addition, since the reinforcing member 92 extends in the front-rear direction along the arrangement position of the battery unit 12, it is possible to effectively improve the mounting rigidity with respect to the tunnel portion 13b.

Moreover, since the reinforcing member 92 extends across the plurality of fastening portions 13c arranged in the front-rear direction, it is possible to further improve the mounting rigidity to the tunnel portion 13b.

In this way, high mounting rigidity with respect to the tunnel portion 13b is obtained in spite of the compact structure, and the central portion of the battery unit 12 is prevented from being displaced in a convex downward direction in the event of a side collision. As a result, the battery unit 12 can be protected without causing inconvenience such as an increase in the weight of the vehicle body.

Moreover, since the horizontal frame 62 having a closed cross section and high rigidity is provided and the horizontal frame 62 is also fixed to the tunnel portion 13b, the effect of protecting the battery unit 12 can be further enhanced.

DESCRIPTION OF SYMBOLS 11... Floor 12... Battery unit 13b... Tunnel part 13c... Fastening part 91... Tunnel reinforcement 92... Reinforcement member

Claims (3)

A lower structure of an electric vehicle in which a battery unit is attached under a floor,
The battery modules of the battery unit are arranged on the left and right sides of a tunnel portion that bulges upward in a substantially arch-shaped cross section at the center of the floor in the vehicle width direction and extends in the vehicle front-rear direction,
The tunnel portion side portion of the battery module is fastened to left and right fastening portions higher than the general surface of the floor in the tunnel portion,
A tunnel reinforcement is provided between the left and right fastening portions to reinforce the tunnel portion between the fastening portions,
A lower structure of an electric vehicle, comprising a reinforcing member that straddles between the fastening portions and is fastened to the tunnel portion with a gap from the tunnel reinforcement. 2. The lower structure of an electric vehicle according to claim 1, wherein said reinforcing member extends in the vehicle front-rear direction along the position where said battery unit is disposed. The battery module is fixed to the tunnel portion by a plurality of the fastening portions arranged in the longitudinal direction of the vehicle,
3. The lower structure of an electric vehicle according to claim 2, wherein said reinforcing member extends across a plurality of said fastening portions.

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