Rear vehicle body structure

Abstract

To absorb an impact load from the vehicle rear even if a battery mounting space is extended to the vehicle rear to increase the battery loading capacity.SOLUTION: A rear vehicle body structure A includes: rear side frames 90 extending in a vehicle fore and aft direction; a rear cross member 95 which is arranged so that front parts of the rear side frames 90 contact therewith from the vehicle rear and extends in a vehicle width direction; a pair of left and right side sills 75 which are spaced apart, by predetermined distances, from the front parts of the rear side frames 90 to the outer sides in the vehicle width direction and extend in the vehicle fore and aft direction; and a rear battery frame 33 which extends in the vehicle width direction at the vehicle rear relative to a battery B and the vehicle front relative to the rear side frames 90. The rear battery frame 33 is mounted on the left and right side sills 75 and on the rear cross member 95.SELECTED DRAWING: Figure 8

Description

Technical Field

[0001] The present disclosure relates to, for example, the rear body structure of an electric vehicle.

Background Art

[0002] For example, Patent Document 1 discloses a vehicle in which a battery is mounted below a floor panel. In this Patent Document 1, side sills are provided on both sides of the passenger compartment, and rear side frames are provided behind the left and right side sills on the rear of the vehicle. The rear side frame has a front and rear extending portion extending in the vehicle front-rear direction, a bent portion that bends obliquely outward in the vehicle width direction at the front end portion of the front and rear extending portion, and an inclined portion extending forward from the bent portion, and the front end portion of the inclined portion is coupled to the side sill. A load transmission member is provided at the coupling portion of the rear side frame with the side sill, and a vulnerable portion formed of a member more vulnerable than other portions is provided.

[0003] In this Patent Document 1, when an impact load acts from the rear of the vehicle, the vulnerable portion of the rear side frame starts to deform earlier than other portions, and thereby, the forward displacement of a rear cross member or the like behind the battery is allowed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, in the case of an electric vehicle, since the amount of battery installed to supply power to the driving motor directly affects the cruising range, there is a demand to increase the amount of battery installed as much as possible. When trying to increase the amount of battery installed in a vehicle where the battery is installed below the floor panel as in Patent Document 1, it is necessary to secure a wide mounting space in the vehicle front-rear direction.

[0006] However, in Patent Document 1, by forming a bent portion and an inclined portion in the rear side frame, the rear side frame is coupled to the side sill, and a load transmission member and a vulnerable portion are provided at the coupling portion and they project inward in the vehicle width direction. Therefore, it is impossible to extend the battery mounting space to the rear of the vehicle. As a result, it has been difficult to increase the amount of battery installed.

[0007] Also, in Patent Document 1, if an attempt is made to extend the battery mounting space to the rear of the vehicle, it becomes impossible to provide a load transmission member and a vulnerable portion. Therefore, countermeasures when an impact load acts from the rear of the vehicle become a problem.

[0008] The present disclosure is in view of such a point, and the object thereof is to be able to absorb an impact load from the rear of the vehicle even when the battery mounting space is extended to the rear side of the vehicle to increase the amount of battery installed.

Means for Solving the Problem

[0009] In order to achieve the above object, in a first aspect of the present disclosure, it is possible to assume a rear body structure of an electric vehicle that includes a traveling motor and in which a battery that supplies power to the traveling motor is disposed below a floor panel. The rear body structure includes a rear side frame that extends in the vehicle longitudinal direction at the rear of the vehicle, a rear side cross member that is disposed such that the front portion of the rear side frame abuts from the rear of the vehicle and extends in the vehicle width direction, a pair of left and right side sills that are separated from the front portion of the rear side frame by a predetermined distance outward in the vehicle width direction and extend in the vehicle longitudinal direction, and a rear side battery frame that extends in the vehicle width direction behind the vehicle and in front of the rear side frame of the battery and protects the battery. A battery case including the rear side battery frame is attached to the left and right side sills and the rear side cross member.

[0010] According to this configuration, an impact load acting from the rear of the vehicle is input to the rear side frame, and the impact load input to the rear side frame is transmitted to the left and right side sills and the rear side battery frame via the rear side cross member. Since the rear side battery frame is a member that protects the battery and has high strength, the input impact load is absorbed by the rear side battery frame. In addition, since the left and right side sills are high-strength members that extend in the vehicle longitudinal direction, the input impact load is also dispersed and absorbed by the left and right side sills. Therefore, it is possible to transmit and absorb the input impact load to the rear side battery frame and the left and right side sills without providing a load transmission member and a vulnerable portion between the rear side frame and the rear portion of the side sill as in Patent Document 1, so that the battery mounting space can be extended to the rear side of the vehicle and the battery mounting amount can be increased.

[0011] In a second aspect of the present disclosure, the battery can be mounted across the virtual straight line from the front portion of the rear side frame toward the front of the vehicle and outside the virtual straight line in the vehicle width direction. According to this configuration, since the battery mounting space becomes wider in the vehicle width direction between the left and right side sills, it is possible to further increase the battery mounting amount.

[0012] In a third aspect of the present disclosure, in a side view of the vehicle, the battery may be mounted up to the rear of the vehicle rather than the rear part of the side sill. According to this configuration, since the mounting space of the battery can be extended rearward of the rear part of the side sill, it becomes possible to further increase the mounting amount of the battery.

[0013] The rear cross member according to the fourth aspect of the present disclosure may be arranged on the upper surface of the rear battery frame and formed to extend along the upper surface of the rear battery frame. The rear cross member and the rear battery frame can be fastened in the vertical direction. According to this configuration, the rear cross member and the rear battery frame can be firmly fixed.

[0014] The rear cross member according to the fifth aspect of the present disclosure can be joined to the lower surface of the floor panel. According to this configuration, the rigidity of the floor panel can be increased by the rear cross member, and the impact load acting on the rear cross member can also be dispersed and absorbed by the floor panel.

[0015] The rear cross member according to the sixth aspect of the present disclosure may have a front plate portion extending in the vertical direction and the vehicle width direction, and a rear plate portion separated from the front plate portion in the vehicle direction and extending in the vertical direction and the vehicle width direction. The vertical dimension of the rear plate portion can be set longer than the vertical dimension of the front plate portion, and the front portion of the rear side frame can be abutted and joined to the rear plate portion from the rear of the vehicle.

[0016] According to this configuration, the rear cross member has the front plate portion and the rear plate portion to become a high-strength member. And by joining the front portion of the rear side frame to the rear plate portion having a relatively long vertical dimension, a wide joint area can be secured and the joint strength can be increased.

Advantages of the Invention

[0017] As described above, the rear battery frame that protects the battery is attached to the left and right side sills and the rear cross member, and the impact load acting on the rear side frame can be dispersed to each member. As a result, even when the mounting space of the battery is extended to the rear side of the vehicle to increase the mounting amount of the battery, the impact load from the rear of the vehicle can be absorbed.

Brief Description of the Drawings

[0018]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Modes for Carrying Out the Invention

[0019] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. It should be noted that the following description of the preferred embodiments is merely illustrative in nature and is not intended to limit the present invention, its applications, or its uses.

[0020] FIG. 1 is a left side view of an electric vehicle (electric car) 1 equipped with a rear body structure A according to an embodiment of the present invention. As shown in FIG. 2, this electric vehicle 1 includes a lower structure body 2 and an upper structure body 3. In FIG. 1, the front bumper, rear bumper, front and rear wheels, etc. are omitted, and they are shown by phantom lines, and each part is schematically shown. In FIG. 2, in addition to the parts omitted in FIG. 1, the door, bonnet hood, front fender, windshield, front and rear lighting devices, interior materials, etc. are omitted, and each part is schematically shown.

[0021] In the description of this embodiment, the front side of the vehicle is simply referred to as "front", the rear side of the vehicle is simply referred to as "rear", the right side of the vehicle is simply referred to as "right", and the left side of the vehicle is simply referred to as "left". The left-right direction of the vehicle is the vehicle width direction.

[0022] As shown in FIG. 1, the electric vehicle 1 is a passenger car. The electric vehicle 1 may be of any type such as a sedan type, hatchback type, one-box type, etc., and its shape is not particularly limited. As shown in FIG. 2, in the electric vehicle 1, a passenger compartment R1 serving as a living space (interior space) for passengers is formed. As shown in FIG. 1, a front seat (seat) S1 is provided on the front side in the passenger compartment R1, and a rear seat S2 is provided behind the front seat S1 in the passenger compartment R1. A luggage compartment R2 is provided behind the rear seat S2 as needed. The passenger compartment R1 and the luggage compartment R2 are provided in the upper structure body 3. Note that only the front seat S1 may be provided in the passenger compartment R1, or a third-row seat (not shown) may be provided behind the rear seat S2.

[0023] On one hand, the space in front of the passenger compartment R1, which is the front part of the electric vehicle 1 (front side space), can be, for example, the power compartment R3. That is, as shown in FIG. 3, the rear body structure A is provided in the electric vehicle 1 including the front side running motor M1 mounted on the front part of the vehicle and the rear side running motor M2 mounted on the rear part of the vehicle, the battery B that supplies power to the running motors M1 and M2, and the battery case 10 in which the battery B is housed. The battery case 10 is disposed below the floor panel 70, which will be described later, and is fixed to the left and right side sills 74 and 75.

[0024] The front side running motor M1 generates a driving force for driving the left and right front wheels FT. The front side power train PT1 is constituted by only this front side running motor M1, or by the front side running motor M1 and a speed reducer, a transmission, etc. Also, the rear side running motor M2 shown in FIGS. 2 and 3 generates a driving force for driving the left and right rear wheels RT (shown in FIG. 1). The rear side power train PT2 is constituted by only this rear side running motor M2, or by the rear side running motor M2 and a speed reducer, a transmission, etc.

[0025] In this embodiment, the rear side running motor M2 is configured to generate a higher maximum output (maximum torque) than the front side running motor M1, and the rear side running motor M2 is larger than the front side running motor M1. Accordingly, the rear side power train PT2 becomes larger than the front side power train PT1. Note that the rear side running motor M2 may generate a lower maximum output than the front side running motor M1, or the rear side running motor M2 and the front side running motor M1 may generate the same maximum output. Also, only the front side power train PT1 may be provided, or only the rear side power train PT2 may be provided. Further, for example, in the case of a large vehicle, larger front side running motors M1 and rear side running motors M2 than those of a small vehicle will be mounted.

[0026] As shown in FIG. 2, the lower structure 2 includes a battery case 10, a pair of left and right front side frames 11 and 12 that extend forward in front of the battery case 10, and a pair of left and right rear frames 13 and 14 that extend rearward behind the battery case 10. The left and right rear frames 13 and 14 extend in the front-rear direction at the rear of the vehicle. Reference numeral 11 indicates the left front side frame, and reference numeral 12 indicates the right front side frame. Also, reference numeral 13 indicates the left rear frame, and reference numeral 14 indicates the right rear frame. In FIG. 2, the lid 35 (described later) of the battery case 10 is removed.

[0027] In the case of a general electric vehicle, the battery case is often made detachable under the floor as a separate body from the vehicle body. However, in this embodiment, not only the battery case 10 but also the left and right front side frames 11 and 12 and the left and right rear frames 13 and 14 are integrated with the battery case 10, and the front side frames 11 and 12 and the rear frames 13 and 14 are also detachable from the upper structure 3 together with the battery case 10.

[0028] Specifically, the electric vehicle 1 of this embodiment is configured to be vertically divisible into a lower structure 2 having a battery case 10 and an upper structure 3 that forms a passenger compartment R1 and a cargo compartment R2. Being vertically divisible means integrating the lower structure 2 with the upper structure 3 using fastening members such as bolts, nuts, and screws without using welding, adhesion, etc. Thereby, when performing maintenance or repair after the electric vehicle 1 is delivered to the user, the lower structure 2 can be separated from the upper structure 3 as needed, improving the maintainability. Note that the fastening members used in the following description also include bolts, nuts, screws, etc.

[0029] Here, as an automobile body structure, a ladder frame type body structure is known. In the case of a ladder frame type body structure, it can be divided vertically into a ladder frame and a cabin. However, since the ladder frame extends continuously in the front-rear direction, it mainly receives collision loads during frontal collisions and rear collisions. During a side collision, the ladder frame only receives the collision load supplementarily, and the cabin mainly receives the collision load. Thus, in a ladder frame type body structure, it is normal for the members receiving the collision load to be separated between frontal and rear collisions and side collisions.

[0030] On the other hand, in the case of the electric vehicle 1 of the present embodiment, the lower structure 2 having the front side frames 11, 12 and the rear frames 13, 14 and the upper structure 3 are separable. However, in both cases of frontal and rear collisions and side collisions, by receiving the collision load with the lower structure 2 and the upper structure 3, the collision load can be dispersed and absorbed by both structures 2 and 3, which is greatly different in its technical idea from the conventional ladder frame type body structure. Hereinafter, the structures of the lower structure 2 and the upper structure 3 will be described in detail.

[0031] (Lower Structure) First, the lower structure 2 will be described. The lower structure 2 includes, in addition to the battery case 10, the front side frames 11, 12 and the rear frames 13, 14, the front and rear power trains PT1, PT2, the front wheels FT, the rear wheels RT, the front suspension device 20 and the rear suspension device 21, etc. The types of the front suspension device 20 and the rear suspension device 21 are not particularly limited.

[0032] The battery case 10 and the battery B housed inside the battery case 10 constitute the battery unit BY. In addition, for example, a battery cooling device or the like may be included in the battery unit BY.

[0033] The battery case 10 is a large case formed below the floor panel 70 of the upper structure 3, spanning from the vicinity of the left end to the vicinity of the right end of the floor panel 70 and from the vicinity of the front end to the vicinity of the rear end of the floor panel 70. By disposing the battery case 10 in a wide range of the lower region of the floor panel 70 in this way, it becomes possible to mount a large-capacity battery B on the electric vehicle 1. The battery B may be, for example, a lithium-ion battery, an all-solid-state battery, or other secondary batteries. Also, the battery B may be a so-called battery cell or a battery pack containing a plurality of battery cells. In the present embodiment, the battery B is constituted by a battery pack, and a plurality of battery packs are mounted in a state of being arranged in the front-rear direction and the left-right direction.

[0034] The battery case 10 includes a left battery frame 30, a right battery frame 31, a front battery frame 32, a rear battery frame 33, a bottom plate 34, and a lid 35 (shown in FIG. 5) that covers the battery B from above. In FIGS. 2 and 3, the state where the lid 35 is removed is shown.

[0035] The left battery frame 30, the right battery frame 31, the front battery frame 32, and the rear battery frame 33 are constituted by, for example, extruded materials made of an aluminum alloy, but may also be constituted by aluminum alloy plates or press-formed materials of steel plates. The bottom plate 34 can also be constituted by an extruded material. In the following description, the "extruded material" refers to an extruded material made of an aluminum alloy, and the "press-formed material" refers to an aluminum alloy plate or a press-formed material of a steel plate. Also, each member may be constituted by, for example, a casting.

[0036] The cross-sectional shapes of the left battery frame 30, the right battery frame 31, the front battery frame 32, and the rear battery frame 33 in the direction orthogonal to their respective longitudinal directions are all rectangular. Also, the left battery frame 30, the right battery frame 31, the front battery frame 32, and the rear battery frame 33 are all arranged at the same height and extend substantially horizontally.

[0037] The left battery frame 30 and the right battery frame 31 are outer battery frames that extend in the front-rear direction outside the vehicle width direction of the battery B. The left battery frame 30 is provided on the left side of the battery case 10 and extends in the front-rear direction along the left side sill 74. The left battery frame 30 is attached to the left side sill 74 by a fastening member or the like. The right battery frame 31 is provided on the right side of the battery case 10 and extends in the front-rear direction along the right side sill 75. The right battery frame 31 is attached to the right side sill 75 by a fastening member or the like.

[0038] Also, the front battery frame 32 is provided at the front of the battery case 10 and extends in the left-right direction. Also, the rear battery frame 33 extends in the left-right direction at the rear of the battery case 10, that is, behind the battery B, and is a member that protects the battery B. Therefore, it is composed of high-strength members.

[0039] The left end of the front battery frame 32 is connected to the front end of the left battery frame 30, and the right end of the front battery frame 32 is connected to the front end of the right battery frame 31. The left end of the rear battery frame 33 is connected to the rear end of the left battery frame 30, and the right end of the rear battery frame 33 is connected to the rear end of the right battery frame 31. Therefore, the left battery frame 30, the right battery frame 31, the front battery frame 32, and the rear battery frame 33 are members that constitute a frame-shaped frame formed to surround all the batteries B in plan view.

[0040] Both the left and right ends of the front battery frame 32 and both the left and right ends of the rear battery frame 33 are attached to the left and right side sills 74, 75 respectively by fastening members or the like. Also, since both the left and right ends of the rear battery frame 33 are connected to the left battery frame 30 and the right battery frame 31, they are attached to the left and right side sills 74, 75 via the left battery frame 30 and the right battery frame 31. Also, both the left and right ends of the rear battery frame 33 may be directly attached to the left and right side sills 74, 75.

[0041] The bottom plate 34 extends substantially horizontally and is fixed to the lower surfaces of the left battery frame 30, the right battery frame 31, the front battery frame 32, and the rear battery frame 33. Also, the lid 35 is fixed to the upper surfaces of the left battery frame 30, the right battery frame 31, the front battery frame 32, and the rear battery frame 33. That is, the lid 35 is attached to the battery frames 30 to 33. The rear battery frame 33 protrudes rearward from the rear part of the lid 35.

[0042] When attaching the lid 35 to the battery frames 30 to 33, for example, fastening members may be used, or adhesion, welding, or the like may be used. Therefore, the left battery frame 30, the right battery frame 31, the front battery frame 32, the rear battery frame 33, the bottom plate 34, and the lid 35 define a battery accommodation space S (shown in FIG. 2) for accommodating the battery B.

[0043] The size of the battery accommodation space S can be changed according to the capacity of the mounted battery B. The size of the battery accommodation space S can be easily changed by changing the lengths of the left battery frame 30, the right battery frame 31, the front battery frame 32, and the rear battery frame 33 and the shape of the bottom plate 34. For example, when the wheelbase is short and the tread is narrow in a small car, the left battery frame 30, the right battery frame 31, the front battery frame 32, and the rear battery frame 33 are shortened, and accordingly, the shapes of the bottom plate 34 and the lid 35 are made smaller, so that the battery accommodation space S becomes smaller according to the small car. On the other hand, in the case of a large car, the left battery frame 30, the right battery frame 31, the front battery frame 32, and the rear battery frame 33 are lengthened, and accordingly, the shapes of the bottom plate 34 and the lid 35 are made larger, so that the battery accommodation space S becomes larger according to the large car. When the left battery frame 30, the right battery frame 31, the front battery frame 32, and the rear battery frame 33 are made of extruded materials, the length can be easily changed. Also, the bottom plate 34 can be made of an extruded material, whereby the shape can be easily changed.

[0044] The upper part of the battery accommodation space S may be closed by the lid 35 or may be closed by the floor panel 70 of the upper structure 3. In the battery accommodation space S, in addition to the battery B, a cooling device for cooling the battery B, a heating device for heating the battery B, etc. (temperature control device) can also be provided. Further, the power of the battery B is supplied to the driving motors M1, M2 via a control device (not shown). Furthermore, the battery B can be charged via a charging socket, a non-contact charger, etc. (not shown).

[0045] As shown in FIG. 2, inside the battery case 10 that constitutes the battery unit BY, first to third in-case members (unit members) 25A, 25B, and 25C are provided as strength members extending in the left-right direction. The heights of the first to third in-case members 25A, 25B, and 25C are all the same and are substantially the same as the height of the left battery frame 30 or the like. The in-case members 25A, 25B, and 25C may be formed of an extruded material or a press-formed material. In this embodiment, three in-case members 25A, 25B, and 25C are provided, but the number of in-case members 25A, 25B, and 25C can be increased or decreased according to the front-rear dimension of the battery case 10. The first to third in-case members 25A, 25B, and 25C are second members.

[0046] The first to third in-case members 25A, 25B, and 25C are arranged at intervals in the front-rear direction, with the first in-case member 25A positioned at the frontmost and the third in-case member 25C positioned at the rearmost. The lower portions of the in-case members 25A, 25B, and 25C are fixed to the upper surface of the bottom plate 34. Also, the left end portions of the in-case members 25A, 25B, and 25C are fixed to the inner surface (right side surface) of the left battery frame 30, and the right end portions of the in-case members 25A, 25B, and 25C are fixed to the inner surface (left side surface) of the right battery frame 31. That is, the in-case members 25A, 25B, and 25C are members that connect the left battery frame 30 and the right battery frame 31.

[0047] Inside the battery case 10, as strength members extending in the front-rear direction, a front central member (member inside the unit) 26 and first to third rear central members (members inside the unit) 27 to 29 are provided. The front central member 26 and the first to third rear central members 27 to 29 are arranged at substantially the same height and are provided at the center in the left-right direction of the battery case 10. The lower end portions of the front central member 26 and the first to third rear central members 27 to 29 are attached to the upper surface of the bottom plate 34. The front central member 26 and the first to third rear central members 27 to 29 are the first members. The front central member 26 and the first to third rear central members 27 to 29 and the first to third in-case members 25A, 25B, 25C intersect with each other.

[0048] The front central member 26 is disposed between the front battery frame 32 and the first in-case member 25A. The front end portion of the front central member 26 is fixed to the center in the left-right direction of the front battery frame 32, and the rear end portion of the front central member 26 is fixed to the center in the left-right direction of the first in-case member 25A. Therefore, the front battery frame 32 is a member that extends so as to connect the front end portions of the left battery frame 30 and the right battery frame 31 and the front end portion of the front central member 26.

[0049] The first rear center member 27 is disposed between the first in-case member 25A and the second in-case member 25B. The front end portion of the first rear center member 27 is fixed to the central portion in the left-right direction of the first in-case member 25A, and the rear end portion of the first rear center member 27 is fixed to the central portion in the left-right direction of the second in-case member 25B. Further, the second rear center member 28 is disposed between the second in-case member 25B and the third in-case member 25C. The front end portion of the second rear center member 28 is fixed to the central portion in the left-right direction of the second in-case member 25B, and the rear end portion of the second rear center member 28 is fixed to the central portion in the left-right direction of the third in-case member 25C. Further, the third rear center member 29 is disposed between the third in-case member 25C and the rear battery frame 33. The front end portion of the third rear center member 29 is fixed to the central portion in the left-right direction of the third in-case member 25C, and the rear end portion of the third rear center member 29 is fixed to the central portion in the left-right direction of the rear battery frame 33. Therefore, the first to third in-case members 25A, 25B, 25C, the front center member 26, and the first to third rear center members 27 to 29 are arranged in a lattice pattern and connected to each other inside the battery case 10, so that the reinforcing effect of the battery case 10 is further enhanced.

[0050] When assuming a virtual straight line extending in the front-rear direction in plan view, the positions in the left-right direction of the front center member 26 and the first to third rear center members 27 to 29 are set so as to be disposed on the virtual straight line. That is, the first to third rear center members 27 to 29 are provided so as to be positioned on the virtual extension line rearward of the front center member 26. Incidentally, the front center member 26 and the first to third rear center members 27 to 29 may be constituted by a single member continuous in the front-rear direction.

[0051] As also shown in FIGS. 5 and 6, the lower structure 2 includes a rear battery frame 33, left and right rear frames 13, 14, and a frame bracket 40, and these members form a part of the rear vehicle body structure A. The rear frames 13, 14 can be formed of, for example, extruded materials, press-formed materials, or the like. In this embodiment, since the rear frames 13, 14 are formed of extruded materials, the cross-sectional shape in the direction orthogonal to the front-rear direction is substantially equal from the front end portion to the rear end portion.

[0052] The left and right rear frames 13, 14 are attached to the rear battery frame 33 that constitutes the rear portion of the battery case 10 via the frame bracket 40. That is, the front portions of the left and right rear frames 13, 14 are connected to the rear battery frame 33 by the frame bracket 40. This frame bracket 40 is made of a member integrally formed using metal and extends in the left-right direction along the rear battery frame 33. The front portions of the left and right rear frames 13, 14 are fixed to the frame bracket 40 using welding, adhesion, fastening members, or the like. The metal constituting the frame bracket 40 is not particularly limited, and for example, aluminum can be mentioned. In this case, the frame bracket 40 can be made of aluminum die-casting.

[0053] The left and right rear frames 13, 14 are attached to the rear battery frame 33 via the frame bracket 40, but the front portions of the rear frames 13, 14 can abut against the rear surface of the rear battery frame 33. Therefore, the rear frames 13, 14 extend rearward from the rear battery frame 33. Incidentally, the front portions of the rear frames 13, 14 may be slightly separated rearward from the rear surface of the rear battery frame 33. Even in this case, overall, it can be said that the rear frames 13, 14 extend rearward from the rear battery frame 33.

[0054] The front part of the left rear frame 13 is arranged to correspond to a position to the left of the lateral center of the rear battery frame 33. Also, the front part of the right rear frame 14 is arranged to correspond to a position to the right of the lateral center of the rear battery frame 33. Thereby, the interval between the left and right rear frames 13 and 14 becomes a predetermined interval. The interval between the rear frames 13 and 14 is set narrower than the interval between the left battery frame 30 and the right battery frame 31 of the battery case 10. Also, the heights of the left and right rear frames 13 and 14 are substantially the same.

[0055] As shown in FIG. 6, the frame bracket 40 includes a vertical plate portion 40a that extends in the vehicle width direction and the vertical and horizontal directions along the rear surface of the rear battery frame 33, and a lower plate portion 40b that extends forward along the lower surface of the rear battery frame 33 from the lower edge portion of the vertical plate portion 40a and also extends in the vehicle width direction. The vertical plate portion 40a and the lower plate portion 40b are fixed to the rear battery frame 33 by a plurality of fastening members and the like described later. In this way, by fixing the vertical plate portion 40a and the lower plate portion 40b of the frame bracket 40 to the rear surface and the lower surface of the rear battery frame 33 respectively, the mounting rigidity of the frame bracket 40 with respect to the rear battery frame 33 can be increased.

[0056] As shown in FIGS. 4 and 5, the frame bracket 40 includes a left outer rib 40c located on the left side of the left rear frame 13, a left inner rib 40d located on the right side of the left rear frame 13, a right outer rib 40e located on the right side of the right rear frame 14, and a right inner rib 40f located on the left side of the right rear frame 14. The left outer rib 40c and the left inner rib 40d suppress the lateral tilting of the left rear frame 13, and the right outer rib 40e and the right inner rib 40f suppress the lateral tilting of the right rear frame 14. Furthermore, since the ribs 40c, 40d, 40e, and 40f are arranged so as to project in the lateral direction of the left and right rear frames 13 and 14, for example, when an impact load acts on the rear frames 13 and 14 from the rear, the ribs 40c, 40d, 40e, and 40f can be used to disperse it over a wide range in the lateral direction.

[0057] The frame bracket 40 is provided with a connecting portion 41 that connects the rear end portions of the left outer rib 40c and the left inner rib 40d and the rear end portions of the right outer rib 40e and the right inner rib 40f. The connecting portion 41 extends in the left - right direction, and the connecting portion 41 connects the middle portions in the front - rear direction of the left and right rear frames 13, 14. That is, in plan view, a rectangular closed cross - section is formed by the left and right rear frames 13, 14, the rear - side battery frame 33, and the connecting portion 41.

[0058] On the left and right sides, which are the outer sides in the vehicle width direction of the frame bracket 40, a pair of left and right arm connecting portions 42, 43 are provided, to which the front portions of the left and right suspension arms 21A, which form part of the rear suspension device 21, are rotatably connected in the vertical direction. The arm connecting portions 42, 43 extend upward beyond the connecting portion 41, and the upper portions of the arm connecting portions 42, 43 are each detachably attached to the upper structure 3.

[0059] At the rear portions of the left and right rear frames 13, 14, a rear suspension cross - member 44 extending in the left - right direction is provided. The rear portions of the left and right rear frames 13, 14 are connected by the rear suspension cross - member 44. On the left and right sides, which are the outer sides in the vehicle width direction of the rear suspension cross - member 44, a pair of left and right arm connecting portions 44a, 44b are provided, to which the rear portions of the left and right suspension arms 21A are rotatably connected in the vertical direction. The arm connecting portions 44a, 44b extend upward, and the upper portions of the arm connecting portions 44a, 44b are each detachably attached to the upper structure 3. Also, in plan view, a rectangular closed cross - section is formed by the left and right rear frames 13, 14, the connecting portion 41, and the rear suspension cross - member 44.

[0060] A sub-frame 46 is provided at the rear part of the lower structure 2. The sub-frame 46 includes a left member 46a that is disposed rearward of the left rear frame 13 and extends in the front-rear direction, a right member 46b that is disposed rearward of the right rear frame 14 and extends in the front-rear direction, and a rear member 46c that connects the rear ends of the left member 46a and the right member 46b.

[0061] The front portions of the left member 46a and the right member 46b of the sub-frame 46 are fixed to the rear suspension cross member 44. That is, the sub-frame 46 is connected to the left and right rear frames 13, 14 via the rear suspension cross member 44. As shown in FIG. 6, in the connected state, the left and right rear frames 13, 14 are positioned below the sub-frame 46.

[0062] (Upper structure) Next, the upper structure 3 will be described. As shown in FIG. 2, the upper structure 3 includes a floor panel 70, a dash panel (partition portion) 71, and a pair of left and right side sills 74, 75. Reference numeral 74 indicates the left side sill, and reference numeral 75 indicates the right side sill.

[0063] The floor panel 70 constitutes the floor surface of the passenger compartment R1, is made of a steel plate or the like that extends in the front-rear direction and also in the left-right direction. The space above the floor panel 70 becomes the passenger compartment R1. A roof 80 is provided above the passenger compartment R1. In addition, front openings 3a and rear openings 3b are respectively formed on both left and right sides of the upper structure 3. As shown in FIG. 1, the front opening 3a and the rear opening 3b can be opened and closed by the front door 81 and the rear door 82 respectively. Although not shown, a front door and a rear door are also disposed on the right side of the upper structure 3 so as to be openable and closable.

[0064] The left and right side sills 74 and 75 are respectively disposed at both left and right ends of the floor panel 70 so as to extend in the front-rear direction. The left end portion of the floor panel 70 is connected to the middle portion in the vertical direction of the left side sill 74, and the right end portion of the floor panel 70 is connected to the middle portion in the vertical direction of the right side sill 75. The upper portions of the side sills 74 and 75 protrude upward from the connection portion of the floor panel 70, and the lower portions of the side sills 74 and 75 protrude downward from the connection portion of the floor panel 70. Since the battery case 10 is disposed below the floor panel 70, the battery case 10 is disposed between the left and right side sills 74 and 75, and in a side view of the vehicle, the lower portions of the side sills 74 and 75 and the battery case 10 overlap.

[0065] The dash panel 71 extends in the vehicle width direction and the vertical direction and is a member for partitioning the passenger compartment R1 and the power compartment R3. The lower end portion of the dash panel 71 is connected to the front end portion of the floor panel 70.

[0066] FIG. 7 is a bottom view of the rear portion of the upper structure 3. As shown in this FIG. 7, the floor panel 70 of the upper structure 3 has a rear panel portion 70A that constitutes the floor surface of the luggage compartment R2. Left and right rear wheel houses 72 and 73 are respectively provided on both left and right sides of the rear panel portion 70A.

[0067] The upper structure 3 includes a pair of left and right rear side frames 90 and 91 that extend in the front-rear direction at the rear of the vehicle. The left rear side frame 90 is formed so as to extend along the left end portion of the rear panel portion 70A inside the vehicle width direction from the left rear wheel house 72. A left crash can 90a is provided at the rear portion of the left rear side frame 90 so as to protrude rearward from the rear portion of the rear panel portion 70A.

[0068] The right rear side frame 91 is formed to extend along the right end portion of the rear panel portion 70A inside the vehicle width direction from the right rear wheel house 73. A right crash can 91a is provided at the rear portion of the right rear side frame 91 so as to protrude rearward from the rear portion of the rear panel portion 70A. A bumper reinforcement 92 extending in the left-right direction is attached to the rear portions of the left crash can 90a and the right crash can 91a. The front side portions of the left and right rear side frames 90, 91 are formed to bend or incline downward.

[0069] Also, as shown in FIGS. 4 and 8, the rear battery frame 33 of the battery case 10 extends in the vehicle width direction in front of the front portions of the rear side frames 90, 91. More specifically, since the battery case 10 is provided below the floor panel 70, the rear battery frame 33 is disposed below the front portions of the rear side frames 90, 91.

[0070] The front portion of the left rear side frame 90 is separated from the rear portion of the left side sill 74 by a predetermined distance rearward and inside the vehicle width direction, and the front portion of the left rear side frame 90 and the rear portion of the left side sill 74 are not connected. Similarly, the front portion of the right rear side frame 91 is separated from the rear portion of the right side sill 75 by a predetermined distance rearward and inside the vehicle width direction, and the front portion of the right rear side frame 91 and the rear portion of the right side sill 75 are not connected. That is, assuming a case where the left rear side frame 90 and the left side sill 74 are connected, the front portion of the rear side frame 90 is extended forward and connected to the rear portion of the side sill 74. Then, the front portion of the rear side frame 90 protrudes inside the vehicle width direction from the rear wheel house 72. Similarly on the right side, the front portion of the rear side frame 91 protrudes inside the vehicle width direction from the rear wheel house 73. When the left and right rear side frames 90, 91 protrude inside the vehicle width direction, the left-right dimension on the rear side of the battery case 10 has to be shortened, and as a result, the mounting amount of the battery B decreases.

[0071] In this embodiment, by disconnecting the rear side frames 90 and 91 and the side sills 74 and 75 respectively, a space is formed in which the battery case 10 can be extended rearward. As a result, the battery case 10 can be extended rearward until the rear side of the battery case 10 approaches the rear wheel houses 72 and 73, and the lateral dimension of the rear side of the battery case 10 can be ensured to be long. Therefore, the mounting amount of the battery B can be increased.

[0072] For example, as shown in FIG. 7, when a virtual straight line L1 extending forward from the central portion in the lateral direction of the front portion of the left rear side frame 90 and a virtual straight line L2 extending forward from the central portion in the lateral direction of the front portion of the right rear side frame 91 are assumed, the battery case 10 (the outer shape is shown by a virtual line) is provided from the region on the left side of the virtual straight line L1 to the region on the right side of the virtual straight line L2. By using such a large-sized battery case 10, the battery B is mounted across the outer side in the vehicle width direction from the virtual straight lines L1 and L2, and the mounting amount of the battery B can be further increased.

[0073] Also, in a side view of the vehicle, the battery case 10 extends rearward beyond the rear portions of the side sills 74 and 75. Therefore, since the rear battery frame 33 is located rearward of the rear portions of the side sills 74 and 75, the battery B can be mounted rearward beyond the rear portions of the side sills 74 and 75.

[0074] Furthermore, when the rear side frames 90 and 91 and the side sills 74 and 75 are disconnected respectively, there may be a problem that there is no direct load transmission path from the rear side frames 90 and 91 to the side sills 74 and 75 when an impact load acts from the rear. However, in this embodiment, even without such a load transmission path, the impact load from the rear can be absorbed by using the battery case 10.

[0075] That is, as shown in FIGS. 8 to 10, the left and right rear side frames 90 and 91 are connected to the rear battery frame 33 by the frame brackets 40. Specifically, the upper structure 3 includes a rear cross member 95, and this rear cross member 95 is arranged such that the front portions of the rear side frames 90 and 91 abut from the rear, and extends in the vehicle width direction. The rear cross member 95 is continuous from the vicinity of the front portion of the left wheel house 72 to the vicinity of the front portion of the right wheel house 73, and includes a front plate portion 95a extending in the vertical and horizontal directions, a rear plate portion 95b arranged away from the front plate portion 95a rearward and extending in the vertical and horizontal directions, and a lower plate portion 95c extending from the lower end portion of the front plate portion 95a to the lower end portion of the rear plate portion 95b. The vertical dimension of the rear plate portion 95b is set to be longer than the vertical dimension of the front plate portion 95a, and the upper end portion of the rear plate portion 95b is located above the upper end portion of the front plate portion 95a. Also, the inclination angles of the front plate portion 95a and the rear plate portion 95b are set such that the front-rear direction interval between the front plate portion 95a and the rear plate portion 95b becomes wider upward.

[0076] The upper end portion of the front plate portion 95a and the upper end portion of the rear plate portion 95b are joined to the lower surface of the floor panel 70, and a closed cross section is formed by the front plate portion 95a, the rear plate portion 95b, the lower plate portion 95c, and the floor panel 70. Thereby, the rigidity of the floor panel 70 can be enhanced.

[0077] The front portions of the rear side frames 90 and 91 abut against the rear plate portion 95b of the rear cross member 95 from the rear, and are joined to the rear plate portion 95b and the lower plate portion 95c. Since the vertical dimension of the rear plate portion 95b is longer than that of the front plate portion 95a, a wide joining area of the rear side frames 90 and 91 with respect to the rear cross member 95 can be ensured.

[0078] As shown in FIG. 8, the rear cross member 95 is disposed on the upper surface of the rear battery frame 33 and is formed to extend along the upper surface of the rear battery frame 33. The rear cross member 95 and the rear battery frame 33 are fastened in the vertical direction, whereby the rear battery frame 33 is detachably attached to the rear cross member 95.

[0079] Specifically, as shown in FIG. 9, the lower surface of a cylindrical nut N1 extending in the vertical direction is fixed to the upper surface of the lower plate portion 95c of the rear cross member 95. Since the nut N1 is to be disposed inside the rear cross member 95, the internal space of the rear cross member 95 can be effectively utilized.

[0080] As shown in FIG. 10, a plurality of nuts N1 are provided at intervals in the left-right direction. Inside the rear cross member 95, a plurality of reinforcing plates 95d are provided corresponding to the number of nuts N1. The reinforcing plate 95d has a through hole 95e through which the upper portion of the nut N1 passes. Since the outer peripheral surface of the nut N1 is welded to the peripheral edge portion of the through hole 95e in a state where the upper portion of the nut N1 passes through the through hole 95e, the fixing strength of the nut N1 can be increased. The front portion of the reinforcing plate 95d is formed along the inner surface of the front plate portion 95a and is welded to the front plate portion 95a. The rear portion of the reinforcing plate 95d is formed along the inner surface of the rear plate portion 95b and is welded to the rear plate portion 95b. Therefore, the front plate portion 95a and the rear plate portion 95b are connected by the reinforcing plate 95d.

[0081] Inside the rear battery frame 33, an intermediate wall portion 33a extending in the front-rear direction and the left-right direction is integrally formed. An insertion hole 33b through which a bolt B1 is inserted from below is formed in this intermediate wall portion 33a. The insertion holes 33b are provided in the same number as the number of nuts N1, and are formed at the same intervals as the intervals between the nuts N1. The nuts N1 are arranged directly above the insertion holes 33b. The bolt B1 inserted through the insertion hole 33b penetrates the upper wall portion of the rear battery frame 33 and also penetrates the lower plate portion 95c and is screwed to the nut N1 from below. By screwing each bolt B1 to each nut N1, the rear cross member 95 and the rear battery frame 33 can be fastened at a plurality of locations. Reference numeral 33c in FIG. 10 is an opening for passing the bolt B1 from below the rear battery frame 33, and a plurality of such openings are formed in the lower wall portion of the rear battery frame 33.

[0082] (Fastening Structure of Frame Bracket) Next, the fastening structure of the frame bracket 40 to the rear battery frame 33 will be described. As shown in FIG. 9, a plurality of nuts N2 are fixed to the inner surface (upper surface) of the lower wall portion of the rear battery frame 33 at intervals in the vehicle width direction. The axes of the nuts N2 extend in the vertical direction and are parallel to the axis of the nut N1.

[0083] On the outer surface (lower surface) of the lower wall portion of the rear battery frame 33, the lower plate portion 40b of the frame bracket 40 is arranged, and a plurality of bolts B2 that are screwed to the nuts N2 penetrate from below through the lower wall portion of the rear battery frame 33 and the lower plate portion 40b of the frame bracket 40. The bolts B2 that penetrate the lower wall portion of the rear battery frame 33 and the lower plate portion 40b of the frame bracket 40 from below are screwed to the nuts N2 from below. By screwing each bolt B2 to each nut N2, the frame bracket 40 and the rear battery frame 33 can be fastened at a plurality of locations.

[0084] In addition, a plurality of nuts N3 are fixed to the inner surface (front surface) of the rear wall portion of the rear battery frame 33. The axes of the nuts N3 extend in the front-rear direction and are orthogonal to the axes of the nuts N1 and N2 in a side view. The plurality of nuts N3 are provided at intervals in the vehicle width direction and are also provided in the upper portion and the lower portion of the rear wall portion of the rear battery frame 33, respectively. On the outer surface (rear surface) of the rear wall portion of the rear battery frame 33, a vertical plate portion 40a of a frame bracket 40 is disposed, and a plurality of bolts B3 that are screwed into the nuts N3 penetrate through the rear wall portion of the rear battery frame 33 and the vertical plate portion 40a of the frame bracket 40. The bolts B3 that penetrate through the rear wall portion of the rear battery frame 33 and the vertical plate portion 40a of the frame bracket 40 from below are screwed into the nuts N3 from the rear. By screwing each bolt B3 into each nut N3, the frame bracket 40 and the rear battery frame 33 can be fastened at a plurality of locations.

[0085] (Operational effects of the embodiment) As described above, according to the present embodiment, the impact load acting from the rear of the vehicle is input to the left and right rear side frames 90 and 91 via the bumper reinforcement 92, and the left and right crash cans 90a and 91a are compressed and deformed. The large impact load that could not be absorbed by this is that the rear battery frame 33 is attached to the left and right side sills 74 and 75 and the rear cross member 95, so the impact load input to the rear side frames 90 and 91 is transmitted to the left and right side sills 74 and 75 and the rear battery frame 33 via the rear cross member 95. Since the rear battery frame 33 is a member that protects the battery B and has high strength, the input impact load is absorbed by the rear battery frame 33. That is, it becomes possible to transmit and absorb the input impact load to the left and right side sills 74 and 75 via the rear battery frame 33, so it is not necessary to directly connect the side sills 74 and 75 and the rear side frames 90 and 91. Therefore, it becomes possible to extend the mounting space of the battery B to the rear side of the vehicle and increase the mounting amount of the battery B.

[0086] In addition, since the left battery frame 30 and the right battery frame 31 are connected to the rear battery frame 33, the impact load input to the rear battery frame 33 can also be dispersed and absorbed by the left battery frame 30 and the right battery frame 31.

[0087] Incidentally, the impact load from the rear is also input to the sub-frame 46 of the lower structure 2. The impact load input to the sub-frame 46 is transmitted to the left and right rear frames 13 and 14 via the rear suspension cross member 44. Therefore, the impact load input to the sub-frame 46 is also transmitted to the rear battery frame 33 via the frame bracket 40 and absorbed.

[0088] The above-described embodiments are merely illustrative in all respects and should not be construed in a limiting sense. Further, all modifications and changes belonging to the equivalent scope of the claims are within the scope of the present invention.

Industrial Applicability

[0089] As described above, the rear vehicle body structure according to the present disclosure can be provided in, for example, an electric vehicle.

Explanation of Signs

[0090] 1 Electric vehicle 10 Battery case 21 Rear suspension device 30 Left battery frame 31 Right battery frame 33 Rear battery frame 40 Frame bracket 70 Floor panel 74, 75 Side sill 90, 91 Rear side frame 95 Rear cross member B Battery

Claims

1. In a rear body structure of an electric vehicle that includes a traveling motor and has a battery for supplying power to the traveling motor disposed below a floor panel, a rear side frame extending in the vehicle longitudinal direction at the rear of the vehicle, a rear side cross member disposed such that a front end surface of the rear side frame abuts from the rear of the vehicle and extending in the vehicle width direction, a pair of left and right side sills extending in the vehicle longitudinal direction and separated from the front end surface of the rear side frame by a predetermined distance outward in the vehicle width direction, a rear side battery frame that extends in the vehicle width direction behind the battery in the vehicle and in front of the rear side frame in the vehicle to protect the battery, a battery case including the rear side battery frame is attached to the left and right side sills and the rear side cross member, a rear body structure in which the rear side frame and the side sill are not connected to each other.

2. In the rear body structure according to Claim 1, a rear body structure in which the battery is mounted across the virtual straight line extending from the front end surface of the rear side frame toward the front of the vehicle and outward in the vehicle width direction from the virtual straight line.

3. In the rear body structure according to Claim 1 or 2, a rear body structure in which the battery case is mounted to the rear of the vehicle beyond the rear portion of the side sill in a side view of the vehicle.

4. In the rear body structure according to any one of Claims 1 to 3, the rear side cross member is disposed on an upper surface of the rear side battery frame and formed to extend along the upper surface of the rear side battery frame, a rear body structure in which the rear side cross member and the rear side battery frame are fastened in the vertical direction.

5. In the rear body structure according to any one of Claims 1 to 4, a rear body structure in which the rear side cross member is joined to a lower surface of the floor panel.

6. In the rear body structure according to any one of Claims 1 to 5, the rear side cross member has a front plate portion extending in the vertical direction and the vehicle width direction, and a rear plate portion separated from the front plate portion toward the rear of the vehicle and extending in the vertical direction and the vehicle width direction, a vertical dimension of the rear plate portion is set to be longer than a vertical dimension of the front plate portion, a rear body structure in which a front end surface of the rear side frame abuts and is joined to the rear plate portion from the rear of the vehicle.

Images