DE102018113460A1 - Body structure for an electric vehicle - Google Patents

Abstract

Task: To effectively disperse an impact load exerted on an electric vehicle from the front of the vehicle on elements forming the body to prevent or reduce the deformation of a front portion of the body. Means for Solving the Problem: A body structure for an electric vehicle includes a front subframe 21 connected to a pair of side members 17 and extending in the vehicle width direction; and a battery box 30, which is disposed on the vehicle rear side of the front subframe 21 and houses a battery unit 30 therein. The body structure includes a battery suspension cross member 25 disposed on the vehicle rear side of the front subframe 21, wherein the battery suspension cross member 25 suspends a front portion of the battery box 30 and is sandwiched between the pair of side members 17 and connected to the side members 17.

Description

Technical area

The present invention relates to a body structure for an electric vehicle.

State of the art

In general, an electric vehicle such as an electric car includes a battery unit in a lower portion of the vehicle. The battery pack includes a plurality of modularized battery modules and is installed under the floor of the vehicle passenger compartment. The battery unit is attached to elements that make up the body.

When a front portion, in which the battery unit is installed, of the electric vehicle is involved in a collision, a large impact force acts on the vehicle passenger compartment. In particular, when the vehicle collides head-on with an obstacle, a large inertial force acts on the battery unit, which has a high weight, to move the battery unit to the vehicle front side. As a result, a load corresponding to the weight of the battery unit is applied to the vehicle passenger compartment, which is disposed above the battery unit.

As a solution to the above problem, the structure disclosed in, for example, Patent Document 1 is well known. In the structure disclosed in Patent Document 1, the battery unit is held by the pair of frame members disposed on the vehicle width direction opposite sides of the battery unit, and the front portions of the frame members are connected to the suspension cross member for holding the front suspension arms.

Reference document list

Patent document

Patent Document 1: JP 5477256 B

Summary of the invention

Problems to be solved by the invention

When a vehicle is subjected to an impact load from the vehicle front side, for example, in a frontal or staggered crash, the impact load is likely to deform a front portion of the vehicle. In order to prevent or reduce such deformation, it is necessary to distribute the impact load among a plurality of elements constituting the front portion of the vehicle.

In the above example, when the vehicle is subjected to an impact load from the vehicle front, the suspension cross member receives the impact load and distributes it to the frame members. The inertial force caused by the impact load to move the battery pack toward the vehicle front is received by the suspension members via the frame members. Consequently, a greater load is exerted on the connections between the suspension cross member and the frame members.

In particular, in a staggered collision, the side portion directly affected in the collision deforms considerably in the vehicle width direction. In such a case, the deformed area may extend to the area where the front portion of the battery unit is suspended. In addition, there is a requirement to maintain the battery pack suspension even under the inertial force that moves the battery pack as described above, i. to prevent or reduce a requirement, damage, drop and the like of the battery pack suspension caused by the inertial force.

The present invention has been made to solve the above problems, and has an object to provide a body structure for an electric vehicle capable of effectively distributing an impact load applied from the vehicle front side to members constituting the body, to prevent or reduce the deformation of the front portion of the body under the impact load.

Means of solving the problems

In order to achieve the above object, the body structure for an electric vehicle according to the present invention comprises: a pair of side members spaced apart in a vehicle width direction; a front subframe connected to the side members and extending in the vehicle width direction; and a battery box disposed on a vehicle rear side of the front subframe and housing a battery unit therein. The body structure for an electric vehicle includes a battery suspension cross member disposed on the vehicle rear side of the front subframe and extending in the vehicle width direction, the battery suspension cross member suspending a front portion of the battery box, and disposed between the pair of side members in the vehicle width direction and connected to the side members is.

Advantageous Effects of the Invention

According to the present invention, when a body having the body structure for an electric vehicle is subjected to an impact load from the vehicle front side, the impact load is effectively distributed to elements constituting the body to prevent the deformation of the front portion of the body under the impact load to reduce.

list of figures

• 1 Fig. 12 is a bottom view of the body structure for an electric vehicle according to the present invention as viewed from below the vehicle.
• 2 is a perspective view of the body structure, from which the wishbone and the front subframe are removed.
• 3 FIG. 12 is a perspective view of the battery suspension cross member and the like of FIG 1 seen from under the vehicle.

Type of embodiment of the invention

With reference to the drawings ( 1 to 3 ), an embodiment of a body structure for an electric vehicle according to the present invention will be described below.

As in 1 1, the electric vehicle according to this embodiment has an electric motor 36 and a gearbox 37 on, which are arranged in a front portion of the vehicle. In particular, the electric motor 36 and the gearbox 37 arranged on the vehicle front side of the (not shown) bulkhead, which forms a front portion of the vehicle passenger compartment. The electric motor 36 provides, for example, power to drive the front wheels 20a the body.

The body structure has a front subframe 21 , a battery box 30 that is a battery unit 31 housed in it, a pair of side panels 17 , a rear convex cross member 19 , a battery suspension cross member 25 and two brackets 27 on.

The battery unit 31 is a power supply device for operating, for example, the electric motor 36 and the same. Although not shown in detail in the drawings, the battery pack includes 31 a variety of modularized battery modules and has a high weight. The battery unit 31 is in the battery box 30 accommodated. The battery box 30 is on the vehicle underside of a floor panel 10 arranged, which forms a bottom portion of the vehicle passenger compartment.

As in the 1 to 3 shown, the battery box extends 30 in the vehicle front / rear direction. The battery box 30 , which is box-shaped, has a bottom portion 30c , a front wall section 30a , a horizontal flange, with a side wall section 30b and a rear wall section (not shown). The battery unit 31 is on the bottom section 30c arranged, which extends in the vehicle front / rear direction. The front wall section 30a stands in the vehicle from a front portion of the bottom section 30c upwards and extends in the vehicle width direction. The front wall section 30a , the flange of the sidewall section 30b , and the rear wall portion are at the bottom of the floor panel 10 added.

The battery box 30 also has a plurality of reinforcing elements 30d . 30e on. In particular, as in the 1 and 3 shown are the reinforcing elements 30d . 30e Front / rear direction of reinforcing elements 30d each of which has an elongated plate shape extending in the vehicle front / rear direction and width direction reinforcing elements 30e each of which has an elongated plate shape extending in the vehicle width direction. The front / rear direction reinforcement elements 30d are each with outer edge portions in the vehicle width direction of the bottom portion 30c connected. Each width direction reinforcement element 30e is with the opposite front / rear direction reinforcement elements 30d and with the bottom section 30c connected. As in 3 is shown in this example, the number of width direction gain elements 30e four, and these four width direction reinforcement elements 30e are spaced apart in the vehicle front / rear direction arranged. The foremost of the width direction reinforcement elements 30e is adjacent to the brackets 27 and disposed on the vehicle rear side, which will be described later.

The battery unit 31 is provided with a power supply cable (not shown) for supplying power to the electric motor 36 and the like connected. The power supply cable is in tubes 35 accommodated. The tubes 35 are in a center tunnel 11 arranged and with the front wall portion 30a of the battery box 30 connected.

As in 3 shown is the center tunnel 11 by a center portion in the vehicle width direction of the floor panel 10 defined, with the central portion bulges up into the vehicle and the center tunnel 11 extends in the vehicle front / rear direction. The center tunnel 11 extends according to this embodiment, the vehicle rear side of the front subframe 21 to the battery unit 31 , Although not shown in the drawings, extends the center tunnel 11 in the vehicle front / rear direction, where he the convex cross member 19 and battery suspension cross member 25 crosses, which will be described later.

As in 1 shown is the front subframe 21 on the vehicle rear side of the electric motor 36 and the transmission 37 arranged so that he is between the front wheels 20a is arranged in the vehicle width direction and extends in the vehicle width direction. A wishbone 20 is at each of the vehicle width direction opposite side portions of the front subframe 21 attached. The front wheels 20a are rotatable on the control arms 20 attached. In 1 become the front wheels 20a shown transparently.

The front subframe 21 has projections in the vehicle width direction opposite outer portions on the vehicle front side 23 on. Every wishbone 20 is through the corresponding projection 23 and a sloping section 22c held, which will be described later.

The front subframe 21 has a convex section 22 on the back of the vehicle. The convex section 22 , the rear edge profile of the front subframe 21 is convex to the vehicle front. The convex section 22 includes a straight section 22a , curved sections 22b and inclined sections 22c ,

The straight section 22a in a center region in the vehicle width direction of the convex portion 22 is arranged, extends approximately straight in the vehicle width direction. The curved sections 22b that are on the vehicle width direction opposite sides of the straight section 22a are arranged, extend contiguous from the straight section 22a and in the vehicle width direction outward, so that they curve to the vehicle rear side.

Every inclined section 22c extends contiguously from the rear end of the corresponding curved section 22b and in the vehicle width direction to the outside, so that it is inclined to the vehicle rear side. The top of a rear section of the inclined section 22c is with a connection section 22d provided on which the rear convex cross member 19 to be connected.

Next are the page elements 17 and the rear convex cross member 19 described. The page elements 17 and the rear convex cross member 19 are sufficiently stiff to form the skeleton of the body. As in 1 shown are the side elements 17 on the opposite sides in the vehicle width direction so as to extend in the vehicle front / rear direction. Upper sections of the page elements 17 are at the bottom of the floor panel 10 added.

Lower sections of the page elements 17 are with the front subframe 21 connected. There is also a strut 15 with an outer portion in the vehicle width direction of each side member 17 connected and extends in the vehicle width direction. The strut 15 extends to the corresponding side skirts 13 , Every side sill 13 that is outside of the corresponding page element 17 is arranged in the vehicle width direction, extends in the vehicle front / rear direction.

The rear convex cross member 19 is in the vehicle width direction inner portions of the side members 17 connected. As in 2 shown are inner portions of the struts in the vehicle width direction 15 and in the vehicle width direction outer portions of the rear convex cross member 19 with the side elements 17 connected so that the vehicle width direction inner portion of each strut 15 to the corresponding in the vehicle width direction outer portion of the rear convex cross member 19 transverse to the corresponding side element 17 has.

As in 1 shown, the side elements extend 17 to the vehicle rear side so as to be inclined outward in the vehicle width direction. In other words, the pair extends side elements 17 so to the vehicle rear, that the distance between increases. As a result, the pair of side members is seen from below the vehicle 17 arranged so that it forms a forward converging shape. The back sections of the side elements 17 extend to the side sills 13 ,

The rear convex cross member 19 standing on the vehicle rear of the front subframe 21 is arranged with a distance therebetween, extends in the vehicle width direction. The rear convex cross member 19 crosses the center tunnel 11 and is with the edges of the center tunnel 11 connected.

As in the 1 and 2 are shown, the vehicle width direction outer portions of the rear convex cross member 19 bent to the vehicle front, and the overall shape of the rear convex cross member 19 is convex seen from below the vehicle to the vehicle rear. In particular, a portion of the rear convex cross member extends in the vehicle width direction 19 approximately straight in the vehicle width direction. In addition, the opposite ends of the central portion are provided with bends, and portions in the vehicle width direction outside the bends extend outward in the vehicle width direction so as to be inclined to the vehicle front side.

As in 1 shown are the front subframe 21 and the rear convex cross member 19 arranged so that the convex section 22 of the front subframe 21 to the rear convex cross member 19 has. Lower portions of the vehicle width direction side portions of the rear convex cross member 19 are with the connection sections 22d connected to the inclined sections 22c of the convex section 22 are provided. Since they are arranged and connected in this way, form the convex portion 22 and the rear convex cross member 19 seen from below the vehicle, a closed frame structure.

Each connection section 22d is placed near a point where the page element 17 in the vehicle width direction of the same side with the front subframe 21 connected is. In this embodiment, the connections are between any two of the side members 17 , the pursuit 15 , the rear convex cross member 19 , the front subframe 21 and the like are arranged on each side in the vehicle width direction within a region near the side in the vehicle width direction of the frame structure close to each other. This increases the rigidity of the body.

As in the 1 to 3 shown, the battery suspension cross member extends 25 which is very stiff in the vehicle width direction. The battery suspension cross member 2 hangs (holds) a front section of the battery box 30 in an upper area in the vehicle. The battery suspension cross member 25 is on the vehicle rear side of the rear convex cross member 19 arranged so as to be arranged in the vehicle width direction between the pair of side members, that is, within the pair of side members 17 is arranged. In the vehicle width direction opposite side portions of the battery suspension cross member 25 are with the page elements 17 connected so that the battery suspension cross member 25 the page elements 17 bridged. The battery suspension cross member 25 has a U-shaped cross-section that opens upwards in the vehicle.

As in the 2 and 3 shown is the battery suspension cross member 25 according to this embodiment bent so that it is the shape of the center tunnel 11 follows. The battery suspension cross member 25 In this example, there are two lower bends 25a which are spaced from each other in the vehicle width direction. The lower bends 25a are in the vehicle width direction opposite side edges of the center tunnel 11 arranged. From the lower bends 25a extends the battery suspension cross member 25 in the vehicle along the side walls of the center tunnel 11 up. Then the battery suspension cross member 25 at upper bends 25b bent, and extends in the vehicle width direction along the ceiling within the center tunnel 11 , In other words, the battery suspension cross member 25 in the vehicle front / rear direction considered a hat shape.

Next is the structure of the two brackets 27 described. As in the 1 and 2 shown, the brackets extend 27 , each of which is plate-shaped, in the vehicle front / rear direction and connect the battery suspension cross member 25 with the battery box 30 , Front sections of the brackets 27 are with the bottoms of the vehicle width direction opposite side portions of the battery suspension cross member 25 connected. In this embodiment, the brackets 27 and the battery suspension cross member 25 in the state with each other with bolts 28 fastened in which the brackets 27 seen from below the vehicle, the battery suspension cross member 25 overlap.

A rear section of each bracket 27 is with the bottom section 30c and the front wall section 30a of the battery box 30 for example, connected by welding. The rear section of the bracket 27 is bent so that it is with the front wall section 30a of the battery box 30 is in surface contact, and further bent so that it coincides with the bottom section 30c of the battery box 30 in surface contact.

The rear section of each bracket 27 is at the corresponding front / rear direction reinforcement element 30d arranged and connected to him. Consequently, the rear portion of each bracket 27 with the corresponding front / rear direction reinforcement element 30d and the bottom section 30c connected in the state in which the holder 27 , the front / rear direction reinforcement element 30d and the bottom section 30c layered on each other.

As in 1 In addition, the body structure according to this embodiment further includes a rear floor cross member (rear cross member). 26 on the vehicle rear side of the battery suspension cross member 25 on. The rear floor cross member 26 who is very stiff is at the Top of the floor panel 10 added. The rear floor cross member 26 extends in the vehicle width direction, wherein it is the pair of side members 17 crosses, and in the vehicle width direction outer portions of the rear floor cross member 26 are with the side skirts 13 connected. In this example, the rear floor cross member 26 to the top of the floor panel 10 attached in the state in which the brackets 27 seen from below the vehicle, the rear floor cross member 26 overlap.

In this embodiment, the frame structure is defined by the convex portion 22 of the front subframe 21 and the rear convex cross member 19 is formed, near the connections between the side elements 17 and the front subframe 21 arranged. In addition, the links between any two of the page elements 17 , the pursuit 15 , the rear convex cross member 19 , the front subframe 21 and the like are arranged in the vehicle width direction of each side within the area near the side in the vehicle width direction of the frame structure close to each other. In other words, the areas each comprising the plurality of connections and thus having increased rigidity are arranged in the front portion of the body. Thus, when subjected to impact load from the vehicle front (in a frontal or staggered crash), the body can absorb this impact load in this highly rigid area.

In doing so, when absorbing the impact load, the elements are deformed to disperse the impact load, and the impact load changes depending on the stress conditions that change during such deformation. The inclusion of the impact load from the vehicle front in the high-stiffness area also stabilizes the function of absorbing the impact load during such deformation. In addition, the page elements 17 , which are arranged so that they form a converging forward shape, and the center tunnel 11 distribute the impact load that has been absorbed in the high-stiffness area to the rear of the vehicle.

When absorbing the impact load becomes an inertial force to the battery unit 31 to move to the vehicle front, generated in the front portion of the vehicle. The load caused by the inertial force acts on the brackets 27 on the battery suspension cross member 25 , This deforms the brackets 27 while the inertial force on the battery suspension cross member 25 acts. In addition, a load to the vehicle front side through the middle tunnel plants 11 continued.

Since they are plate-shaped, are the brackets 27 with the underside of the battery suspension cross member 25 in surface contact, as well as with the bottom section 30c of the battery box 30 in area contact. This increases the strength against the load acting in the vehicle front / rear direction.

The impact load from the vehicle front side is planted over the side elements 17 to the vehicle back. The inertial force is mainly planted through the center tunnel 11 to the front of the vehicle.

That the side elements 17 are arranged to form a forward converging shape, the impact load from the vehicle front side is planted outside the brackets 27 continued. As a result, the load caused by the inertial force is less implanted to the side members 17 as the center tunnel 11 continued. Consequently, the page elements 17 , which are arranged so that they form a forward converging shape, capable of effectively propagating an impact load to the vehicle rear side.

At this time, a load in the front / rear direction acts on the center tunnel 11 in the area between the rear convex cross member 19 and the battery suspension cross member 25 , Accordingly, although not shown in the drawings, it may be advantageous to advance the rigidity of the portion between the rear convex cross member 19 and the battery suspension cross member 25 of the center tunnel 11 to increase.

This also prevents excessive loading on the brackets 27 is exercised, thus, reliably holding the battery unit 31 allows.

The rear floor cross member 26 In addition to the above elements, it allows the impact load on the rear floor cross member 26 from the front of the vehicle to the floor panel 10 and the side sills 13 to distribute. In addition, the inertial force acts around the battery unit 31 to move on the battery suspension cross member 25 , planted through the center tunnel 11 continues, and causes a strain on the rear floor cross member 26 pulls to the vehicle front. Consequently, the area where the rear floor crossmember 26 is arranged to absorb the load sufficiently.

As can be seen from the above description, the use of the Body structure for an electric vehicle according to this embodiment, the following effects. That is, when subjected to an impact load from the vehicle front (in a frontal or staggered crash), the body can effectively distribute the impact load among many elements. This prevents or reduces the deformation of the front portion of the body.

The above embodiment has been described for illustrative purposes only and does not limit the present invention which is defined by the claims. The configuration of each portion of the present invention is not limited to one described in the above embodiment, and various modifications can be made within the technical scope defined by the claims of the present invention.

Although, for example, the front section of the battery box 30 with the brackets 27 with the battery suspension cross member 25 in the above embodiment, the present invention is not limited thereto. Alternatively, the front portion of the battery box 30 with the battery suspension cross member 25 be connected.

LIST OF REFERENCE NUMBERS

10

floor panel

11

center tunnel

13

side skirts

15

strut

17

page element

19

to the rear convex cross member

20

wishbone

20a

front

21

front subframe

22

convex section

22a

straight section

22b

curved section

22c

inclined section

22d

connecting portion

23

head Start

25

Battery suspension crossmember

25a

lower bend

25b

upper bend

26

rear floor cross member (rear cross member)

27

bracket

28

bolt

30

battery box

30a

Front wall section

30b

Sidewall portion

30c

bottom section

30d

Front / rear direction reinforcing element

30e

Width direction reinforcing element

31

battery unit

35

tubular member

36

electric motor

37

transmission

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• JP 5477256 B [0005]

Claims (5)

A body structure for an electric vehicle, comprising: a pair of side members spaced from each other in a vehicle width direction; a front subframe connected to the side members and extending in the vehicle width direction; and a battery box disposed on a vehicle rear side of the front subframe and housing a battery unit therein, the body structure being characterized by comprising: a battery suspension cross member disposed on the vehicle rear side of the front subframe and extending in the vehicle width direction; the battery suspension cross member suspends a front portion of the battery box and is disposed between the pair of side members in the vehicle width direction and connected to the side members. Body structure for an electric vehicle after Claim 1 wherein the pair of side members extend toward the vehicle rear side so as to increase a distance therebetween. Body structure for an electric vehicle after Claim 1 or 2 vehicle body comprising: a rear convex cross member disposed on the vehicle rear side of the front subframe and connected to the side members, the rear convex cross member being convex in a vehicle width direction central portion toward the vehicle rear side, a rear portion of the front subframe a convex portion which is convex toward a vehicle front side, and the convex portion and the rear convex cross member form a frame structure. Body structure for an electric vehicle according to one of Claims 1 to 3 wherein in the vehicle width direction opposite side portions of the battery suspension cross member are provided with plate-shaped brackets extending in a vehicle front / rear direction, and the brackets are connected to the battery suspension cross member and the battery box and connect the battery suspension cross member to the battery box. Body structure for an electric vehicle after Claim 4 wherein the brackets overlap the battery suspension cross member as viewed from below the vehicle.

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