阅读说明：本技术 车辆的后部车身结构 (Rear body structure of vehicle ) 是由 森本诚 中山伸之 久保田阳满 一色泰范 平川太一 于 2018-05-01 设计创作，主要内容包括：车辆的后部车身结构包括；后副车架,设置在后纵梁的下方,沿车身前后方向延伸。后副车架具备相对于车身后部上所设置的重要安全构件而向车身后侧延伸且相对于所述重要安全构件而位于车身后侧的前侧负荷吸收部及后侧负荷吸收部,所述前侧负荷吸收部及所述后侧负荷吸收部在来自车身后方的碰撞负荷作用时吸收该碰撞负荷,所述后侧负荷吸收部设置在所述前侧负荷吸收部的车身后侧,且该后侧负荷吸收部的抗轴向压缩强度被设定得低于所述前侧负荷吸收部。(A rear body structure of a vehicle includes; and the rear auxiliary frame is arranged below the rear longitudinal beam and extends along the front-rear direction of the vehicle body. The rear subframe includes a front side load absorbing portion and a rear side load absorbing portion that extend toward the vehicle body rear side with respect to an important safety member provided at the vehicle body rear portion and are located at the vehicle body rear side with respect to the important safety member, the front side load absorbing portion and the rear side load absorbing portion absorbing a collision load from the vehicle body rear side when the collision load acts, the rear side load absorbing portion being provided at the vehicle body rear side of the front side load absorbing portion, and an axial compression strength of the rear side load absorbing portion being set lower than that of the front side load absorbing portion.)

1. A rear vehicle body structure of a vehicle, characterized by comprising:

a rear side member extending in the front-rear direction of the vehicle body at the rear of the vehicle body; and

the rear auxiliary frame is arranged below the rear longitudinal beam and extends along the front-rear direction of the vehicle body; wherein the content of the first and second substances,

the rear subframe includes a front side load absorbing portion and a rear side load absorbing portion that extend toward the vehicle body rear side with respect to an important safety member provided at the vehicle body rear portion and are located at the vehicle body rear side with respect to the important safety member, the front side load absorbing portion and the rear side load absorbing portion absorbing a collision load from the vehicle body rear side when the collision load acts,

the rear side load absorbing portion is provided on the vehicle body rear side of the front side load absorbing portion, and the axial compression strength of the rear side load absorbing portion is set lower than that of the front side load absorbing portion.

2. The rear vehicle body structure of the vehicle according to claim 1, characterized in that:

the rear subframe includes a frame connecting portion that is provided between the front side load absorbing portion and the rear side load absorbing portion, that is connected to the front side load absorbing portion and the rear side load absorbing portion, and that is connected to the rear side member.

3. The rear vehicle body structure of the vehicle according to claim 2, characterized in that:

the front side load absorbing portion and the rear side load absorbing portion each have a closed cross-section portion formed in a closed cross-section shape on an orthogonal cross-section orthogonal to the vehicle body longitudinal direction,

the frame connecting portion has a load transmitting portion extending in a vehicle body front-rear direction, the load transmitting portion transmitting an impact load from a vehicle body rear side from the front side load absorbing portion to the rear side load absorbing portion when the impact load acts,

the load transmission portion is formed in a closed cross-sectional shape identical to the closed cross-sectional shape of the front side load absorbing portion and the closed cross-sectional shape of the rear side load absorbing portion on an orthogonal cross-section orthogonal to the vehicle body longitudinal direction.

4. The rear vehicle body structure of the vehicle according to claim 3, characterized in that:

the closed cross-section portion of the front side load absorbing portion, the closed cross-section portion of the rear side load absorbing portion, and the load transmitting portion of the frame connecting portion are formed in a cross-sectional polygonal shape having a larger number of sides than a cross-sectional quadrilateral shape,

the frame connecting portion includes a peripheral wall portion formed in a closed cross section in an orthogonal cross section orthogonal to a vehicle width direction, and is formed in such a manner that: in the peripheral wall portion, a vehicle body front side of the load transmission portion is butted joined to a vehicle body front side of the peripheral wall portion, and a vehicle body rear side of the load transmission portion is butted joined to a vehicle body rear side of the peripheral wall portion.

5. The rear vehicle body structure of the vehicle according to any one of claims 1 to 4, characterized in that:

an attachment other than the important safety member is provided at a position overlapping the front side load absorbing portion in the vehicle body front-rear direction.

6. The rear vehicle body structure of the vehicle according to any one of claims 1 to 5, characterized in that:

the rear subframe includes a cross member having a closed cross section, the cross member extending in the vehicle width direction below the rear side member at a position on the vehicle body rear side of the important safety member, and both end portions being connected to the rear side member,

the front end of the front side load absorbing portion is connected to the beam portion.

Technical Field

The present invention relates to a rear vehicle body structure of a vehicle, and more particularly to a rear vehicle body structure of a vehicle including a rear subframe provided below a rear side member.

Background

Vehicles such as automobiles are known to have the following structure: a rear subframe for supporting an engine, a transmission, and the like is provided below a rear side member extending in the vehicle body front-rear direction at the rear portion of the vehicle body, and the rear subframe is coupled to the rear side member.

For example, patent document 1 discloses the following structure: a rear sub frame is provided below the rear side member, and the rear sub frame is coupled to the rear side member. For example, patent document 2 discloses the following structure: an engine mounting rear subframe and a transmission mounting rear subframe are provided below the rear portion of the vehicle body, the engine mounting rear subframe is fixed to the vehicle frame, and the transmission mounting rear subframe is fixed to the engine mounting rear subframe and the vehicle frame.

There are following requirements for vehicles such as automobiles: when a rear-side collision (rear collision) occurs and a collision load acts from the rear of the vehicle body, the safety of the occupant in the vehicle compartment can be improved. There are also requirements for a vehicle in which a rear sub frame is provided below a rear side member, as follows: the safety of the occupant in the vehicle interior can be improved in the event of a rear collision.

In addition, in a vehicle such as an electric vehicle having a rear sub-frame provided below a rear side member, when important safety members such as an engine, a generator, and a fuel tank are provided in a rear portion of a vehicle body, it is required to protect the important safety members provided in the rear portion of the vehicle body when a rear collision occurs and a collision load acts from the rear of the vehicle body.

Disclosure of Invention

The present invention aims to provide a rear vehicle body structure of a vehicle, which is provided with a rear sub frame arranged below a rear side frame, and comprises: in the event of a rear collision, the collision load can be absorbed to protect important safety members provided at the rear of the vehicle body, and the safety of occupants in the vehicle compartment can be improved.

The rear vehicle body structure of a vehicle of the present invention includes: a rear side member extending in the front-rear direction of the vehicle body at the rear of the vehicle body; the rear auxiliary frame is arranged below the rear longitudinal beam and extends along the front-rear direction of the vehicle body; the rear subframe includes a front side load absorbing portion and a rear side load absorbing portion that extend toward the vehicle body rear side with respect to an important safety member provided at the vehicle body rear portion and are located at the vehicle body rear side with respect to the important safety member, the front side load absorbing portion and the rear side load absorbing portion absorbing a collision load from the vehicle body rear side when the collision load acts, the rear side load absorbing portion being provided at the vehicle body rear side of the front side load absorbing portion, and an axial compression strength of the rear side load absorbing portion being set lower than that of the front side load absorbing portion.

Drawings

Fig. 1 is a bottom view of a vehicle body to which a rear vehicle body structure of a vehicle according to a first embodiment of the present invention is applied.

Fig. 2 is a side view of a vehicle body to which the above-described rear vehicle body structure is applied.

Fig. 3 is a bottom view of the vehicle body shown in fig. 1 with the subframe unit and the battery frame removed.

Fig. 4 is a bottom view of the vehicle body shown in fig. 1 with a portion of the subframe unit removed.

Fig. 5 is a sectional view of the vehicle body taken along line Y5-Y5 in fig. 3.

Fig. 6 is a sectional view of the vehicle body taken along line Y6-Y6 in fig. 1.

Fig. 7 is a perspective view of the subframe unit.

Fig. 8 is a perspective view of the subframe unit with the attachment removed.

Fig. 9 is a side view of the subframe unit shown in fig. 8.

Fig. 10 is a bottom view of the subframe unit shown in fig. 8.

Fig. 11 is a perspective view showing a frame connecting portion connecting the rear subframe and the rear side member.

Fig. 12 is a perspective view showing a branch frame member of the subframe unit.

Fig. 13 is a perspective view showing a frame coupling portion that couples the rear sub-frame and the battery frame.

Fig. 14 is another perspective view showing a frame connecting portion that connects the rear sub-frame and the battery frame.

Fig. 15 is a perspective view showing a lower frame member of the subframe unit.

FIG. 16 is a cross-sectional view of the rear subframe unit taken along line Y16-Y16 of FIG. 10.

Fig. 17 is an explanatory view for explaining attachment of the attachment to the rear sub frame.

Fig. 18 is an explanatory view for explaining a rear side branch hanger supporting a muffler.

Fig. 19 (a) to (c) are explanatory views for explaining the movement of the muffler when the rear collision occurs.

Fig. 20 is a bottom view of a vehicle body to which a rear vehicle body structure of a vehicle according to a second embodiment of the present invention is applied.

Fig. 21 is a side view of a vehicle body to which the above-described rear vehicle body structure is applied.

Fig. 22 is a perspective view showing a main portion of the rear vehicle body structure.

Fig. 23 is a cross-sectional view of a connection portion between the lower frame member and the upper cross member.

Fig. 24 is a sectional view of a coupling portion between the lower frame member and the battery frame.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Fig. 1 is a bottom view of a vehicle body to which a rear vehicle body structure of a vehicle according to a first embodiment of the present invention is applied, fig. 2 is a side view of the vehicle body to which the rear vehicle body structure of the vehicle is applied, fig. 3 is a bottom view of the vehicle body shown in fig. 1 with a subframe unit and a battery pack removed, fig. 4 is a bottom view of the vehicle body shown in fig. 1 with a part of the subframe unit removed, fig. 5 is a cross-sectional view of the vehicle body taken along the line Y5-Y5 in fig. 3, and fig. 6 is a cross-sectional view of the vehicle body taken along the line Y6-Y6 in fig. 1.

The vehicle body 1 to which the rear body structure of the vehicle according to the embodiment of the present invention is applied is a body of an electric vehicle or the like including a drive motor as a drive source for driving the vehicle and a battery for storing electric power supplied to the drive motor. The vehicle body 1 is provided with a range extending device for increasing a cruising distance. The range extending device includes a generator that generates power for traveling supplied to a battery, and an engine that is a drive source that drives the generator. In the vehicle body 1, a drive motor is provided at a front portion of the vehicle body, a battery is provided below a floor portion of a vehicle compartment, and a range extending device is provided at a rear portion of the vehicle body.

As shown in fig. 1 to 6, the vehicle body 1 is provided at a rear portion of the vehicle body with a pair of left and right rear side frames 2 extending in the front-rear direction of the vehicle body and a rear sub frame 50 extending in the front-rear direction of the vehicle body along the left and right rear side frames 2 below the left and right rear side frames 2. The rear side member 2 and the rear sub frame 50 are formed of plate-shaped members made of a metal material.

The rear part of the vehicle body is also provided with: a rear floor portion 3 formed of a rear floor, which is erected on the left and right rear side members 2 and extends in the front-rear direction of the vehicle body; a first cross member 4 is bridged between the left and right rear side frames 2 below the rear floor 3.

The rear floor 3 has an opening 3a for installing a range extender 40 in which a generator 41 for generating traveling electric power to be supplied to the battery 20 and an engine 42 for driving the generator 41 are integrally assembled. The first cross member 4 is provided on the vehicle body front side of the opening portion 3 a.

The rear side member 2 is formed into a substantially U-shaped cross section, is attached to the lower surface of the rear floor 3, and is formed into a substantially quadrangular closed cross section extending in the front-rear direction of the vehicle body together with the rear floor 3. The first cross member 4 is formed into a substantially hat-shaped cross section, is attached to the lower surface of the rear floor 3, and is formed into a closed cross-section having a substantially quadrangular cross section extending in the vehicle width direction together with the rear floor 3.

Crush cans 6 as load absorbing portions extending in the vehicle body front-rear direction are provided at the vehicle body rear ends of the left and right rear side frames 2. The crush boxes 6 are attached to both end portions of a side member side bumper reinforcement 5 provided in a rear bumper (not shown) extending in the vehicle width direction, respectively.

As shown in fig. 5, the crush can 6 is formed: the cross section substantially orthogonal to the longitudinal direction, i.e., the axial direction, of the vehicle body is a closed cross section having a substantially polygonal cross section with more sides than a square. Specifically, the crush can 6 has a closed-section portion 6a having a substantially cross-shaped cross section and has a plurality of recesses 6b extending in a direction substantially orthogonal to the axial direction. According to this structure, when the crush can 6 is acted upon by the collision load from the rear of the vehicle body, it is collapsed and deformed to absorb the collision load.

The crush can 6 is integrally formed in a closed cross-section by hydroforming or the like of a pipe member, but may be formed in a substantially cross-sectional shape by joining a first plate-like member formed to protrude outward in the vehicle width direction in a cross-sectional convex shape and a second plate-like member formed to protrude inward in the vehicle width direction in a cross-sectional convex shape.

As shown in fig. 2, the crush can 6 is fastened and joined to the rear side frame 2 by a first plate member 7 and a second plate member 8 by bolts and nuts, the first plate member 7 is fixed to the crush can 6 by welding or the like and extends in a direction substantially orthogonal to the vehicle body front-rear direction, and the second plate member 8 is fixed to the rear side frame 2 by welding or the like and extends in a direction substantially orthogonal to the vehicle body front-rear direction.

In the vehicle body 1, the rear side frame 2 is formed in a closed cross-section together with the rear floor 3, but the rear side frame 2 may be formed in a closed cross-section having a substantially quadrangular cross-section by itself. Further, the crush can 6 is provided on the vehicle body rear side of the rear side member 2 via the first plate member 7 and the second plate member 8, but the crush can 6 may be integrally formed with the rear side member 2.

In the vehicle body 1, the crush cans 6 are provided in the rear side frames 2, so that the portions of the rear side frames 2 of the crush cans 6 serve as load absorbing portions, that is, portions having lower axial compression strength than other portions of the rear side frames 2. However, the axial compression strength may be reduced by setting the thickness of a part of the steel plate forming the rear side member 2 to be thin, and the load absorbing portion may be provided in the rear side member 2.

The front end of the rear side member 2 is joined to the rear end of the upper bent member 9 so as to overlap therewith, and the front end of the upper bent member 9 is joined to a second cross member 12 which extends in the vehicle width direction and is bridged between the left and right side sills 11. The kick-up member 9 is positioned further outward in the vehicle width direction toward the vehicle body front side and inclined toward the vehicle body lower side. The left and right rocker beams 11 are provided so as to extend in the vehicle body longitudinal direction on both sides in the vehicle width direction of a vehicle interior floor portion 10 formed by a front floor that forms a floor surface of the vehicle interior.

The left and right kick-up beams 9 are provided with kick-up portions 13 formed of kick-up plates, and the kick-up portions 13 extend obliquely upward of the vehicle body as extending from the rear end portion of the cabin floor portion 10 toward the rear side of the vehicle body. The rear floor portion 3 is provided so as to extend from the kick portion 13 toward the vehicle body rear side.

The kick beam 9 is formed in a hat shape in cross section, is attached to the lower surface of the kick portion 13, and is formed in a closed cross-sectional shape having a substantially quadrangular cross section extending in the vehicle body front-rear direction together with the kick portion 13. The second cross member 12 is formed into a substantially hat-shaped cross section, is attached to the lower surface of the cabin floor 10, and is formed into a substantially quadrangular closed cross section extending in the vehicle width direction together with the cabin floor 10.

As shown in fig. 3, a floor tunnel portion 14 that extends in the vehicle body front-rear direction and that bulges upward toward the vehicle body upper side is formed at the vehicle width direction center of the cabin floor portion 10. A floor member 15 extending in the vehicle body longitudinal direction is attached substantially at the center between the floor tunnel portion 14 and the left and right rocker members 11, and tunnel reinforcements 16 are attached to both sides of the floor tunnel portion 14 in the vehicle width direction. The floor frame 15 and the tunnel reinforcement 16 are formed into a hat shape in cross section and joined to the vehicle compartment floor 10.

In the vehicle body 1, a battery 20 is provided below the cabin floor 10. As shown in fig. 6, the battery 20 is attached to a battery holder 30 that supports the battery 20 in a state of being attached to the battery tray 21, and the battery holder 30 is supported by the vehicle body 1 by being coupled to the cabin floor portion 10.

The battery frame 30 includes: a front member (not shown) provided on the front side of the vehicle body and extending in the vehicle width direction; a rear member 31 provided on the rear side of the vehicle body and extending in the vehicle width direction; and side members 32 connected to both vehicle width direction sides of the front member and both vehicle width direction sides of the rear member 31, respectively, and extending in the vehicle body front-rear direction. The side members 32 on both sides are provided on the vehicle body lower side of the left and right floor frames 15 and attached to the floor frames 15.

As shown in fig. 6, the front member, the rear member 31, and the side members 32 on both sides are each composed of a battery frame upper member 33 having a substantially L-shaped cross section on the vehicle upper side constituting the battery frame 30 and a battery frame lower member 34 having a substantially L-shaped cross section on the vehicle lower side constituting the battery frame 30, and are formed into a closed cross-sectional shape having a substantially quadrangular cross section by joining the battery frame upper member 33 and the battery frame lower member 34. The battery frame 30 is provided with a flange portion 30a extending substantially horizontally on the inside in the vehicle width direction, and the battery 20 is supported by the battery frame 30 by attaching the battery tray 21 to the flange portion 30 a.

The battery frame 30 is specifically a side member 32, and is provided substantially along the floor member 15 and is coupled to the floor member 15. As shown in fig. 6, the frame connecting portion 35 that connects the battery frame 30 and the floor frame 15 is connected by a bolt B1 and a nut N1 when the upper surface portion 30B of the battery frame 30 overlaps the bottom surface portion 15a of the floor frame 15. The plurality of frame connecting portions 35 are provided in the vehicle body longitudinal direction of the side member 32.

In the vehicle body 1, a range extender 40 including a generator 41 and an engine 42 is provided at the rear of the vehicle body. Since the generator 41 uses a high voltage, the range extender 40 is an attachment which is an important safety member, and is provided in the opening 3a of the rear floor portion 3 so as to protrude toward the vehicle upper side and the vehicle lower side with respect to the rear floor portion 3.

Further, at the rear of the vehicle body, a muffler 44 and a catalyst device 45 as exhaust system components are provided in an exhaust pipe 43 extending from the engine 42. The muffler 44 is a device for reducing the exhaust sound of the engine 42 when released to the atmosphere, and the catalyst device 45 is a device for purifying the exhaust gas of the engine 42. The muffler 44 and the catalyst device 45 are not members which are important safety members, and are provided so as to extend in the vehicle width direction on the vehicle body lower side of the rear floor portion 3. Specifically, the catalytic device 45 is provided on the vehicle body rear side of the range-extending device 40, and the muffler 44 is provided on the vehicle body rear side of the catalytic device 45. The muffler 44 and the catalytic device 45 are integrally connected by a connecting member 46.

The accessory members provided at the rear portion of the vehicle body, specifically, the range extender 40, the muffler 44, and the catalyst 45 are integrally assembled to the rear subframe 50 to form a subframe unit 60 as an integral unit, and the subframe unit 60 is assembled to the vehicle body 1 as a whole. In this way, the attachment 40, 44, 45 and the rear subframe 50 provided at the rear portion of the vehicle body are provided as the integral unit 60, so that the attachment can be easily incorporated into the vehicle body 1, and productivity and safety in manufacturing the vehicle body can be improved.

Further, a torsion beam type suspension device having a pair of left and right trailing arms (not shown) extending in the front-rear direction of the vehicle body and a torsion beam 17 (see the broken line in fig. 2) connecting the pair of left and right trailing arms and extending in the vehicle width direction is provided in the rear portion of the vehicle body. In the vehicle body 1, the torque beam 17 is provided on the vehicle body front side of the range extending device 40 and on the vehicle body rear side of the battery frame 30 on the vehicle body upper side of a lower frame member 71 of a rear subframe 50 described later.

Fig. 7 is a perspective view of the subframe unit, fig. 8 is a perspective view of the subframe unit with the attachment removed, fig. 9 is a side view of the subframe unit shown in fig. 8, and fig. 10 is a bottom view of the subframe unit shown in fig. 8. As shown in fig. 7 to 10, the subframe unit 60 is configured by integrally assembling the range extender 40, the muffler 44, and the catalyst device 45 to the rear subframe 50.

The rear sub-frame 50 includes: an upper side frame member 51 extending in the vehicle body front-rear direction along the rear side member 2; a branch frame member 61 coupled to the upper frame member 51 and branched to extend from the center side in the vehicle body longitudinal direction of the upper frame member 51 toward the vehicle body front side and the vehicle body lower side; and a lower frame member 71 provided on the vehicle body lower side with respect to the upper frame member 51 and extending from the branch frame member 61 to the vehicle body front side in a substantially horizontal direction.

Further, a sub-frame side bumper reinforcement 18 provided in a rear bumper (not shown) extending in the vehicle width direction is connected to the rear sub-frame 50, and vehicle body rear ends of the left and right upper side frame members 51 are connected to both end portions of the sub-frame side bumper reinforcement 18, respectively. The rear subframe 50 is formed symmetrically in the vehicle width direction.

The upper frame member 51 includes: left and right upper frame portions 52 extending in the vehicle body front-rear direction along the left and right rear side members 2, respectively; and an upper cross member portion 53 extending in the vehicle width direction and connecting the vehicle width direction center sides of the left and right upper frame portions 52 to each other.

The upper frame portion 52 includes a load absorbing portion 54, and the load absorbing portion 54 is formed in a closed cross-section shape, extends toward the vehicle body rear side with respect to the range-extending device 40, and absorbs a collision load when the collision load from the vehicle body rear acts at a position on the vehicle body rear side of the range-extending device 40.

As shown in fig. 8, the load absorbing portion 54 includes a front side load absorbing portion 54a provided on the front side of the vehicle body and a rear side load absorbing portion 54b provided on the rear side of the vehicle body with respect to the front side load absorbing portion 54 a. The front side load absorbing portion 54a and the rear side load absorbing portion 54b are formed in the same closed cross-sectional shape on an orthogonal cross-section substantially orthogonal to the vehicle body longitudinal direction, and have a closed cross-sectional portion formed in a substantially cross-sectional shape similarly to the crush can 6. The rear side load absorbing portion 54b is formed so that the thickness of the steel plate is thinner than that of the front side load absorbing portion 54a, and the axial compression strength is set low.

The front load absorbing portion 54a and the rear load absorbing portion 54b are each formed in a substantially cross-sectional shape by joining a first plate-like member formed to protrude outward in the vehicle width direction in a cross-sectional convex shape and a second plate-like member formed to protrude inward in the vehicle width direction in a cross-sectional convex shape. However, the structure of the load absorbing portions 54a and 54b is not limited to this.

In the vehicle body 1, the muffler 44 and the catalyst device 45 are provided on the front side of the load absorbing portion 54 of the rear subframe 50 in the vehicle body so as to overlap the load absorbing portion 54, specifically, the front side load absorbing portion 54a in the vehicle body front-rear direction (see fig. 2).

The upper frame portion 52 further includes a front frame portion 55 located on the front side of the vehicle body with respect to the load absorbing portion 54. The vehicle body rear side of the front side frame portion 55 is formed in a closed cross-sectional shape having a substantially hexagonal cross-section, and the vehicle body front side of the front side frame portion 55 is formed in a closed cross-sectional shape having a substantially quadrangular cross-section.

As shown in fig. 4, the front side frame portion 55 extends to be positioned further outward in the vehicle width direction than the vehicle body front side, and is connected to the vehicle body front side of the rear side frame 2 by a bolt and a nut. The front frame portion 55 is formed so that the thickness of the steel plate is greater than the thickness of the front load absorbing portion 54a and the rear load absorbing portion 54b, and the axial compression strength is set high.

As shown in fig. 2, the crush cans 6 (hereinafter, sometimes referred to as load absorbing portions 6) which are the load absorbing portions on the side of the side member provided in the rear side member 2 and the load absorbing portions 54 on the side of the sub-frame provided in the rear sub-frame 50 are provided as follows: the rear end portion of the sub-frame side load absorbing portion 54 is provided on the vehicle body front side with respect to the rear end portion of the side-rail side load absorbing portion 6, and the front end portion of the sub-frame side load absorbing portion 54 is provided on the vehicle body front side with respect to the front end portion of the side-rail side load absorbing portion 6.

Further, the upper frame portion 52 is provided with a plurality of frame coupling portions 56 that couple the rear sub frame 50 and the rear side frame 2, and the plurality of frame coupling portions 56 are provided at intervals in the vehicle body longitudinal direction. The vehicle body 1 is provided with a front side frame coupling portion 56a and a rear side frame coupling portion 56b that couple the load absorbing portion 54 of the rear subframe 50 and the rear side frame 2.

Fig. 11 is a perspective view showing a frame coupling portion that couples the rear subframe and the rear side member, and shows a frame coupling member 80 that constitutes the rear side frame coupling portion 56 b. The rear side frame coupling portion 56b couples the rear subframe 50 and the rear side frame 2 provided in proximity to the rear subframe 50 via the frame coupling member 80.

As shown in fig. 11, the frame coupling member 80 includes: a peripheral wall portion 83 extending in the vehicle width direction and formed in a closed cross-section having a substantially quadrangular cross section in an orthogonal cross section orthogonal to the vehicle width direction; and a load transmission portion 84 provided in the peripheral wall portion 83 and extending in the vehicle body longitudinal direction. Peripheral wall portion 83 is formed by joining upper beam 81 having a substantially u-shaped cross section on the upper side of the vehicle body constituting frame connecting member 80 and lower beam 82 having a substantially u-shaped cross section on the lower side of the vehicle body constituting frame connecting member 80.

The peripheral wall portion 83 is formed in a closed cross-section including an upper surface portion 83a, a lower surface portion 83b, and side surface portions 83c on both sides in the vehicle body longitudinal direction. The load transmission portion 84 has a closed cross-section portion 84a formed in a substantially cross-sectional shape by joining a first plate-like member 85 formed in a convex cross-section to a second plate-like member 86 formed in a convex cross-section.

The closed-section surface 84a of the load transmission portion 84 is formed in the same shape as the closed-section surface of the front side load absorbing portion 54a and the closed-section surface of the rear side load absorbing portion 54b of the rear subframe 50. The load transmission portion 84 is formed by abutting the vehicle body front side of the load transmission portion 84 against the vehicle body front side of the peripheral wall portion 83 and abutting the vehicle body rear side of the load transmission portion 84 against the vehicle body rear side of the peripheral wall portion 83 in a state where the side surface portions 85a on both sides of the first plate-like member 85 are engaged with the side surface portions 86a on both sides of the second plate-like member 86.

A bolt insertion hole 83d is formed in the upper surface portion 83a and the lower surface portion 83B on the vehicle width direction outer side of the frame connecting member 80, and a cylindrical member 87 formed in a substantially cylindrical shape corresponding to the bolt insertion hole 83d and through which a bolt B2 is inserted is fixed to the upper surface portion 83 a.

The frame connecting member 80 is provided between the front side load absorbing portion 54a and the rear side load absorbing portion 54b so that the closed cross-sectional portion 84a of the load transmission portion 84, the closed cross-sectional portion of the front side load absorbing portion 54a, and the closed cross-sectional portion of the rear side load absorbing portion 54b coincide with each other in the vehicle body longitudinal direction, and is joined and connected to the front side load absorbing portion 54a and the rear side load absorbing portion 54 b.

Further, in a state where the frame connecting member 80 is disposed on the vehicle body lower side of the rear side member 2 in such a manner that the bolt insertion hole 83d provided in the upper surface portion 83a of the frame connecting member 80 corresponds to the bolt insertion hole 2B provided in the lower surface portion 2a of the rear side member 2 shown in fig. 3, the frame connecting member 80 is connected to the rear side member 2 by a bolt B2 being screwed to a nut (not shown) welded to the vehicle body upper side of the lower surface portion 2a of the rear side member 2.

The front side frame coupling portion 56a also couples the rear sub frame 50 and the rear side member 2 via the frame coupling member 80, the frame coupling member 80 includes a peripheral wall portion 83 and a load transmission portion 84 formed similarly to the rear side frame coupling portion 56b, a bolt insertion hole 83d is formed on the vehicle width direction outer side of the frame coupling member 80, and a cylindrical member 87 is fixed to the upper surface portion 83 a.

In the front side frame coupling portion 56a, the frame coupling member 80 is provided between the front side load absorbing portion 54a and the front side frame portion 55 so that the closed cross-sectional portion 84a of the load transmitting portion 84 and the closed cross-sectional portion of the front side load absorbing portion 54a coincide with each other in the vehicle body longitudinal direction, and is joined and coupled to the front side load absorbing portion 54a and the front side frame portion 55.

The frame connecting member 80 of the front side frame connecting portion 56a is also connected to the rear side frame 2 by screwing the frame connecting member 80 to a nut welded to the vehicle body upper side of the lower surface portion 2a of the rear side frame 2 with a bolt B2 in a state where the frame connecting member 80 is provided on the vehicle body lower side of the rear side frame 2 in correspondence with the bolt insertion hole 83d provided in the upper surface portion 83a of the frame connecting member 80 and the bolt insertion hole 2B provided in the lower surface portion 2a of the rear side frame 2.

The left and right frame connecting members 80 constituting the front side frame connecting portion 56a are connected by a sub frame cross member 90 formed in a closed cross section shape and extending in the vehicle width direction. The subframe cross member 90 has both ends in the vehicle width direction joined to the peripheral wall portions 83 of the left and right frame connecting members 80 to form the upper side cross member portion 53. The sub-frame cross member 90 is further provided with an inclined surface 90a (see fig. 10 and 16) on the vehicle width direction center side, the inclined surface 90a is inclined so as to be positioned further toward the vehicle body front side than the vehicle body lower side, and a guide plate (guide portion 91) described later is attached to the inclined surface 90 a.

Fig. 12 is a perspective view showing a branch frame member of the subframe unit. As shown in fig. 12, the branch frame member 61 includes: a rear surface portion 62 provided on the vehicle body rear side and extending obliquely so as to be located on the vehicle body lower side toward the vehicle body front side; a front surface portion 63 provided on the vehicle body front side and extending toward the vehicle body lower side in a substantially vertical direction; a bottom surface portion 64 provided on the vehicle body lower side and extending in the substantially horizontal direction in the vehicle body front-rear direction; the side surface portions 65 are provided on both sides of the rear surface portion 62, the front surface portion 63, and the bottom surface portion 64, respectively, which are connected to each other at inner and outer ends in the vehicle width direction and are spaced apart from each other in the vehicle width direction in a direction substantially orthogonal to the vehicle width direction.

The side surface portion 65 of the branch frame member 61 is formed in a substantially rectangular trapezoid shape having a longer length in the vehicle longitudinal direction on the vehicle upper side than on the vehicle lower side, and the side surface portion 65 is formed with a substantially inverted triangle-shaped opening portion 65 a. The branch frame member 61 is joined to the upper frame member 51 by joining flange portions 66 extending toward the vehicle upper side, provided on the side surface portions 65 on both sides, to the upper frame member 51.

Fig. 13 is a perspective view showing a frame coupling portion that couples the rear subframe and the battery frame, fig. 14 is another perspective view showing the frame coupling portion that couples the rear subframe and the battery frame, and fig. 15 is a perspective view showing a lower frame member of the subframe unit.

As shown in fig. 13 to 15, in the frame connecting portion 70 that connects the rear subframe 50 and the battery frame 30, the lower frame member 71 of the rear subframe 50 is connected to the battery frame 30. The lower frame member 71 includes a closed cross-section portion 74, and the closed cross-section portion 74 is formed into a closed cross-section by joining a frame upper member 72 having a substantially U-shaped cross-section on the upper side of the vehicle body constituting the lower frame member 71 and a frame lower member 73 having a substantially U-shaped cross-section on the lower side of the vehicle body constituting the lower frame member 71, and an orthogonal cross-section orthogonal to the front-rear direction of the vehicle body.

The vehicle width direction inner side of the lower frame member 71 is linearly provided along the vehicle body front-rear direction, and the vehicle width direction outer side of the lower frame member 71 extends obliquely so as to be positioned further outward in the vehicle width direction than the vehicle body front side. That is, the lower frame member 71 is formed in a substantially right-angled triangular shape having a width in the vehicle width direction larger on the vehicle body front side than on the vehicle body rear side in plan view.

As shown in fig. 15, a first concave portion 75 is formed in the upper surface portion 71a of the lower frame member 71 and in the vehicle width direction center portion of the vehicle body front side end portion, the first concave portion 75 is recessed in a substantially quadrangular pyramid shape so as to form a ridge line extending in the vehicle body front-rear direction inside the closed cross-section portion 74, a second concave portion 76 is formed in the lower surface portion 71b and in the vehicle width direction center portion of the vehicle body front side end portion, and the second concave portion 76 is recessed in a substantially quadrangular prism shape so as to form a ridge line extending in the vehicle body front-rear direction inside the closed cross-section portion 74.

The lower frame member 73 of the lower frame member 71 is provided with a front extension 73a and a rear extension 73b that extend toward the front side and the rear side of the vehicle body with respect to the upper frame member 72, respectively.

The lower frame member 71 is coupled to the battery frame 30 by a nut (not shown) fixed to the upper surface side of the bottom surface portion 30c of the battery frame 30 and a bolt B3 screwed to the nut, in a state in which the vehicle body front side of the closed cross-section portion 74 is provided so as to face the battery frame 30 and the forward extending portion 73a overlaps the bottom surface portion 30c of the battery frame 30. Further, the frame lower member of the rear member 31 extends to cover the side member 32 on the vehicle body rear side of the side member 32 of the battery frame 30.

As shown in fig. 1 and 13, the side member 32 of the battery frame 30 extends in the vehicle longitudinal direction at the vehicle longitudinal direction center side with respect to the rear subframe 50, and is offset outward in the vehicle width direction with respect to the rear subframe 50. Specifically, the side member 32 extends in the vehicle longitudinal direction such that a center line C2 of the side member 32 is offset outward in the vehicle transverse direction with respect to a center line C1 of the rear subframe 50 in the vehicle transverse direction (i.e., a line extending in the vehicle longitudinal direction through the center of the load absorbing portion 54 in the vehicle transverse direction).

The lower frame member 71 includes: an inclined portion 77 extending obliquely so as to be positioned further outward in the vehicle width direction than the vehicle body front side and facing the side member 32; the widened portion 78 extends from the inclined portion 77 inward in the vehicle width direction to a position where the widened portion 78 extends linearly in the vehicle body longitudinal direction and faces the rear member 31.

The inclined portion 77 is formed by a portion of the lower frame member 71 on the outer side in the vehicle width direction, and the widened portion 78 is formed by a portion of the lower frame member 71 on the inner side in the vehicle width direction on the vehicle body front side. The vehicle body rear side of the lower frame member 71 is formed so that the width in the vehicle width direction is substantially equal to the width of the upper frame member 51 and the branch frame member 61.

The lower frame member 71 is coupled to the branch frame member 61 by a nut (not shown) fixed to the upper surface side of the bottom surface portion 64 of the branch frame member 61 and a bolt B4 screwed into the nut, in a state where the vehicle body rear side of the closed cross-section portion 74 is provided so as to face the front surface portion 63 of the branch frame member 61 and the rear extension portion 73B overlaps the bottom surface portion 64 of the branch frame member 61.

FIG. 16 is a cross-sectional view of the subframe unit taken along line Y16-Y16 of FIG. 10. As shown in fig. 16, the rear subframe 50 is provided with a guide portion 91 formed of a guide plate, and the guide portion 91 extends obliquely so as to be located further toward the vehicle body front side and further toward the vehicle body lower side than the muffler 44 and the catalyst device 45 on the vehicle body rear side with respect to the range extender 40, and guides the muffler 44 when a collision load from the vehicle body rear side acts.

The guide portion 91 includes a vertical wall portion 92 extending obliquely so as to be located further toward the vehicle body front side than the vehicle body lower side, and extends to the vehicle body lower side with respect to the range extending device 40 so as to cover the range extending device 40 from the vehicle body rear side. The vertical wall portion 92 is provided with a plurality of, specifically, three recessed portions 92a extending in the vehicle vertical direction and recessed toward the vehicle front side, and thereby a plurality of ridges extending in the vehicle vertical direction are formed on the guide portion 91 based on the recessed portions 92 a.

As shown in fig. 8, mounting brackets 93 formed in a substantially hat-shaped cross section are attached to both sides in the vehicle width direction on the vehicle body front side of the guide portion 91 so as to cover the vehicle body front side of the recessed portion 92 a. As shown in fig. 16, the guide portion 91 is coupled to the upper side cross member portion 53 by the mounting bracket 93 being mounted to the inclined surface 90a of the subframe cross member 90 by bolts and nuts. The guide portion 91 extends toward the vehicle body rear side with respect to the upper side beam portion 53, and a portion 91a extending toward the vehicle body rear side with respect to the upper side beam portion 53 is supported by the upper side beam portion 53 in an overhanging state.

The guide portion 91 includes a bottom surface portion 94 extending from the vehicle body lower side to the vehicle body front side of the vertical wall portion 92. The flange portions 94a provided on both sides of the bottom surface portion 94 in the vehicle width direction are connected to the bottom surface portion 64 of the branch frame member 61 by bolts B4 and nuts together with the rearward extending portion 73B of the lower frame member 71, and the flange portions 92B provided on both sides of the vertical wall portion 92 in the vehicle width direction below the vehicle body are connected to the rear surface portion 62 of the branch frame member 61 by bolts B5 and nuts (see fig. 10 and 13).

The guide portion 91 is connected to the front end portion of the load absorbing portion 54 provided in the upper frame member 51 via the upper cross member portion 53, and is connected to the bottom surface portion 64 of the branch frame member 61 and the rear extension portion 73b of the lower frame member 71. The bottom surface 94 of the guide portion 91 can also be used as a jack contact portion that comes into contact with a jack, for example, during maintenance work.

Fig. 17 is an explanatory view for explaining attachment of the attachment to the rear sub frame, showing a part related to attachment of the attachment. In the drawings other than fig. 17 to 19, the mounting structure of the accessory on the rear subframe 50 is omitted for illustration. As shown in fig. 17, the range extender 40 is attached to the upper frame member 51 of the rear subframe 50 via an elastic member by the left and right side support portions 40a provided on both sides in the vehicle width direction, and is attached to the subframe cross member 90 via an elastic member by the rear support portion 40b provided on the vehicle body rear side.

The muffler 44 and the catalyst device 45 are mounted to the rear subframe 50 by a front side hanger 100 and a rear side hanger 110 provided on the vehicle body rear side with respect to the front side hanger 100.

Forward side strut hanger 100 includes: a muffler side link 101 fixed to both sides in the vehicle width direction of the exhaust pipe 43 located upstream of the muffler 44 and having a distal end portion extending in the vehicle width direction; a sub-frame side link 102 fixed to the frame connecting member 80 of the rear side frame connecting portion 56b of the rear sub-frame 50 and having a distal end portion extending in the vehicle width direction; a rubber member 103 as an elastic body which is penetrated by the muffler-side link 101 and the sub-frame-side link 102.

The rubber member 103 is formed of an elastic material such as rubber into a substantially elliptical plate shape. The rubber member 103 is provided with insertion holes 103a and 103b extending in the axial direction of the rubber member 103 and through which the muffler-side link 101 and the sub-frame-side link 102 are inserted, respectively. In the rubber member 103 of the front side bracket 100, two insertion holes 103a, 103b are provided to extend in the vehicle width direction at a distance in the vehicle body front-rear direction.

The distal end portion of the muffler side connecting rod 101 includes a muffler side through-hole 101a extending in the vehicle width direction and penetrating through the insertion hole 103a of the rubber member 103. The distal end portion of the sub-frame side link 102 includes a sub-frame side through portion 102a that extends in the vehicle width direction and is inserted through the insertion hole 103b of the rubber member 103.

The front side hanger 100 passes through the muffler side through portion 101a of the muffler side link 101 and the sub-frame side through portion 102a of the sub-frame side link 102 into the insertion holes 103a and 103b of the rubber member 103, respectively, and thereby supports the muffler 44 and the catalytic device 45 to the rear sub-frame 50 via the rubber member 103.

Fig. 18 is an explanatory view for explaining a rear side branch hanger supporting a muffler, schematically showing a part related to the rear side branch hanger. As shown in fig. 17 and 18, rear side bracket hangers 110 are provided on both sides in the vehicle width direction on the vehicle body rear side of muffler 44. Rear lateral strut hanger 110 includes: a muffler-side link 111 fixed to the muffler 44 and having a distal end portion extending in the vehicle body longitudinal direction; sub-frame side links 112 fixed to the sub-frame side bumper reinforcement 18 of the rear sub-frame 50 and having distal end portions extending in the vehicle body longitudinal direction; and a rubber member 113 as an elastic body which is penetrated through the muffler side link 111 and the sub-frame side link 112.

The rubber member 113 is formed of an elastic material such as rubber into a substantially elliptical plate shape. The rubber member 113 is provided with insertion holes 113a and 113b extending in the axial direction of the rubber member 113 and through which the muffler-side link 111 and the sub-frame-side link 112 are inserted, respectively. In the rubber member 113 of the rear side bracket 110, two insertion holes 113a and 113b are provided to extend in the vehicle body front-rear direction at intervals in the vehicle body vertical direction and the vehicle width direction.

The muffler-side link 111 includes a muffler-side through-hole 111a extending in the vehicle body longitudinal direction and passing through an insertion hole 113a of the rubber member 113 at a distal end portion thereof, and an elastic body movement restricting portion 111b bent at a position on the vehicle body front side with respect to the muffler-side through-hole 111a, the elastic body movement restricting portion 111b restricting movement of the rubber member 113 toward the vehicle body front side with respect to the muffler-side through-hole 111 a.

The sub-frame side link 112 includes a sub-frame side passage portion 112a extending in the vehicle body longitudinal direction at a distal end portion and passing through an insertion hole 113b of the rubber member 113, and a sub-frame side passage allowing portion 112b extending straight in the vehicle body longitudinal direction by a predetermined distance on the vehicle body rear side of the sub-frame side passage portion 112a in succession to allow passage through the insertion hole 113 b.

The sub-frame side link 112 further includes an elastic body penetration limiting portion 112c, and the elastic body penetration limiting portion 112c is bent at the vehicle body rear side of the sub-frame side penetration allowing portion 112b to limit a portion located at the vehicle body rear side with respect to the sub-frame side penetration allowing portion 112b to penetrate through the rubber member 113.

The rear side bracket 110 is inserted through the muffler side through-hole 111a of the muffler side link 111 and the sub-frame side through-hole 112a of the sub-frame side link 112 into the insertion holes 113a and 113b of the rubber member 113, respectively, and supports the muffler 44 on the rear sub-frame 50 via the rubber member 113.

Fig. 19 is an explanatory diagram for explaining the movement of the muffler when a rear collision occurs. As shown in fig. 19 (a), in the event of a rear collision of the vehicle body 1, a collision load acts from the rear of the vehicle body, the rear portion of the vehicle body deforms, and the collision load is input to the rear side frame 2, and the collision load is also input to the rear sub frame 50.

When a collision load is input to the rear subframe 50, as shown in fig. 19 (b), the subframe-side bumper reinforcement 18 of the rear subframe 50 moves toward the vehicle front side, and the rear-side load absorbing portion 54b of the rear subframe 50 is buckled and deformed in the vehicle front-rear direction, thereby absorbing the collision load.

When the sub-frame side bumper reinforcement 18 of the rear sub-frame 50 moves toward the vehicle body front side, the sub-frame side penetration allowing portion 112b provided in the sub-frame side link 112 of the rear side hanger 110 moves toward the vehicle body front side and penetrates through the insertion hole 113b of the rubber member 113. Thus, the collision load can be absorbed by the rear load absorbing portion 54b of the rear subframe 50 without moving the muffler side link 111 of the rear side hanger 110.

As shown in fig. 19 (c), when the subframe-side bumper reinforcement 18 of the rear subframe 50 moves further toward the vehicle front side, the front load absorbing portion 54a of the rear subframe 50 is buckled and deformed in the vehicle front-rear direction to absorb the collision load, and the muffler 44 and the catalyst device 45 move toward the vehicle front side. However, the muffler 44 and the catalyst device 45 move further toward the vehicle body lower side along the guide portion 91 toward the vehicle body front side.

When the sub-frame side bumper reinforcement 18 moves further toward the vehicle body front side, the penetration of the sub-frame side link 112 into the rubber member 113 is restricted by the elastic body penetration restricting portion 112c provided in the sub-frame side link 112 of the rear side bracket 110, and the movement of the rubber member 113 toward the vehicle body front side is restricted by the elastic body movement restricting portion 111b provided in the muffler side link 111 of the rear side bracket 110. Thus, the muffler 44 and the catalyst device 45 move further toward the vehicle body lower side along the guide portion 91 toward the vehicle body front side, and the muffler side link 111 of the rear side bracket 110 is disengaged from the rubber member 113.

In the vehicle body 1 thus configured, when a rear collision occurs and a collision load acts from the rear of the vehicle body, after the collision load is input to the rear side frame 2, the collision load is absorbed by the load absorbing portion 6 provided in the rear side frame 2, and the load input to the rear side frame 2 is transmitted to the vehicle body front side of the rear side frame 2 and dispersed.

Further, when the load absorbing portion 6 provided in the rear side member 2 starts buckling deformation, the collision load is also input to the rear subframe 50, and the load absorbing portion 54 provided in the rear subframe 50 buckles and deforms to absorb the collision load. In the rear subframe 50, after buckling deformation of the rear side load absorbing portion 54b, the front side load absorbing portion 54a is buckled and deformed to absorb the collision load.

The load input to the rear subframe 50 is transmitted from the upper frame member 51 of the rear subframe 50 to the vehicle front side, transmitted to the rear side frame 2 coupled to the vehicle front side of the rear subframe 50, transmitted to the vehicle front side, transmitted from the upper frame member 51 of the rear subframe 50 to the lower frame member 71 via the branch frame members 61, and transmitted from the lower frame member 71 to the battery frame 30. At this time, the load input to the branch frame member 61 is mainly transmitted from the rear face portion 62 and the side face portions 65 on both sides of the vicinity thereof to the lower frame member 71 through the bottom face portion 64 and the side face portions 65 on both sides of the vicinity thereof.

Further, the load input to the rear subframe 50 is transmitted to the rear surface portion 62 of the branch frame member 61 and the side surface portions 65 on both sides of the vicinity thereof through the upper side cross member portion 53 and the guide portion 91, is transmitted to the lower side frame member 71, and is transmitted from the lower side frame member 71 to the battery frame 30.

When a rear collision occurs and a collision load acts on the guide portions 91 from the rear of the vehicle body, the collision load input to the guide portions 91 is transmitted to the rear surface portion 62 of the branch frame member 61 and the side surface portions 65 on both sides of the vicinity thereof, to the lower frame member 71, from the lower frame member 71 to the battery frame 30, from the upper cross member portion 53 to the upper frame member 51 of the rear subframe 50, and to the respective portions of the rear subframe 50.

In the vehicle body 1 according to the present embodiment, as shown in fig. 2, the rear subframe 50 provided below the rear side frame 2 includes a front side load absorbing portion 54a and a rear side load absorbing portion 54b that extend toward the vehicle body rear side with respect to the range extending device 40 (hereinafter referred to as the important safety member 40) which is an important safety member provided at the vehicle body rear portion and are located at the vehicle body rear side with respect to the important safety member 40, and the axial compression strength of the rear side load absorbing portion 54b is set lower than that of the front side load absorbing portion 54 a.

As shown in fig. 8, the rear subframe 50 includes a rear side frame coupling portion 56b provided between the front side load absorbing portion 54a and the rear side load absorbing portion 54b, coupled to the front side load absorbing portion 54a and the rear side load absorbing portion 54b, and coupled to the rear side frame 2. The frame coupling portion 56b is constituted by a frame coupling member 80.

As described above, in the vehicle rear body structure according to the present embodiment, the rear subframe 50 provided below the rear side frame 2 includes the front side load absorbing portion 54a and the rear side load absorbing portion 54b that extend toward the vehicle body rear side with respect to the important safety member 40 provided at the vehicle body rear portion and are provided at the vehicle body rear side of the important safety member 40, and the rear side load absorbing portion 54b is set to have a lower axial compression strength than the front side load absorbing portion 54 a.

Thus, at the time of a rear collision, the rear subframe 50 can cause buckling deformation of the front side load absorbing portion 54a after buckling deformation of the rear side load absorbing portion 54b, which is spaced apart from the important safety members 40, so that at the time of a rear collision, the collision load can be absorbed in the order of the rear side load absorbing portion 54b and the front side load absorbing portion 54a of the rear subframe 50, and the important safety members 40 provided at the rear portion of the vehicle body can be protected by the rear subframe 50. In addition, in the event of a rear collision, the rear load absorbing portion 54b and the front load absorbing portion 54a of the rear subframe 50 absorb the collision load in this order, and the rear subframe 50 can improve the safety of the occupant in the vehicle interior.

The rear subframe 50 further includes a rear side frame coupling portion 56b provided between the front side load absorbing portion 54a and the rear side load absorbing portion 54b, coupled to the front side load absorbing portion 54a and the rear side load absorbing portion 54b, and coupled to the rear side member 2. Thus, the front side load absorbing portion 54a and the rear side load absorbing portion 54b are coupled to the rear side frame coupling portion 56b coupled to the rear side frame 2, and therefore, compared to the case where the front side load absorbing portion 54a and the rear side load absorbing portion 54b are integrally formed, the bending rigidity can be improved, and the rear side load absorbing portion 54b and the front side load absorbing portion 54a can be effectively buckled and deformed at the time of a rear collision.

The rear side frame connecting portion 56b has a load transmission portion 84 extending in the vehicle body longitudinal direction, and the load transmission portion 84 is formed in the same closed cross-sectional shape as the closed cross-sectional portion of the front side load absorbing portion 54a and the closed cross-sectional portion of the rear side load absorbing portion 54 b. This enables the collision load to be efficiently transmitted from the rear side load absorbing portion 54b to the front side load absorbing portion 54a at the time of a rear collision. Further, as compared with the case where the cross-sectional shape is different from the closed cross-sectional portions of the front side load absorbing portion 54a and the rear side load absorbing portion 54b, the bending rigidity can be improved, and the rear side load absorbing portion 54b and the front side load absorbing portion 54a can be effectively buckled and deformed at the time of a rear collision.

The closed cross-section of the front side load absorbing portion 54a, the closed cross-section of the rear side load absorbing portion 54b, and the load transmitting portion 84 of the rear side frame coupling portion 56b are formed in a polygonal cross-sectional shape having more sides than a square cross-sectional shape. As a result, more ridges can be provided than in the case of forming the cross-sectional quadrilateral shape, and the axial compression strength can be improved, and the above-described effects can be obtained more effectively.

If the load transmission portion 84 is joined to the peripheral wall portion 83 by the flange portions provided at the vehicle body front side end portion and the vehicle body rear side end portion, respectively, stress concentration occurs at portions other than the flange portions of the vehicle body front side end portion and the vehicle body rear side end portion of the load transmission portion 84 and deformation occurs at the time of a rear collision, which may cause failure in effective absorption of the collision load. However, according to the above embodiment, since the vehicle body front side of the load transmission portion 84 is brought into abutting engagement with the vehicle body front side of the peripheral wall portion 83, and the vehicle body rear side of the load transmission portion 84 is brought into abutting engagement with the vehicle body rear side of the peripheral wall portion 83, it is possible to suppress the occurrence of stress concentration, and at the time of a rear collision, it is possible to effectively absorb the collision load by the front side load absorbing portion 54a and the rear side load absorbing portion 54 b.

Further, the accessories 44, 45 other than the important safety member 40 are provided at positions overlapping the front side load absorbing portion 54a in the vehicle body front-rear direction. This can protect the important safety member 40 during a rear collision, and can prevent damage to the attachments 44 and 45 provided at positions overlapping the front load absorbing portion 54a in the vehicle body longitudinal direction when only the rear load absorbing portion 54b is buckled and deformed.

Next, a rear vehicle body structure of a vehicle according to a second embodiment of the present invention will be described.

Fig. 20 is a bottom view of a vehicle body to which a rear vehicle body structure of a vehicle according to a second embodiment of the present invention is applied, and fig. 21 is a side view of the vehicle body to which the rear vehicle body structure is applied. Fig. 22 is a perspective view showing a main portion of the rear vehicle body structure. The basic rear vehicle body structure of the second embodiment and the rear vehicle body structure of the first embodiment are common to each other. Therefore, in the following description, the same reference numerals are used for the components common to the first embodiment, and the description thereof will be omitted or simplified, and the differences from the first embodiment will be mainly described.

In the first embodiment described above, the upper side cross member portion 53 of the rear subframe 50 is constituted by the front side frame connecting portions 56a (frame connecting members 80) joined to the front surfaces of the left and right front side load absorbing portions 54a, respectively, and the subframe cross member 90 of a closed cross section joined and connected between these front side frame connecting portions 56 a. In contrast, in the second embodiment, the upper side cross member portion 53 is constituted by the cross member reinforcement 120 extending in the vehicle width direction and joined to the front surfaces of the left and right front side load absorbing portions 54a, respectively, and the frame member 122 joined to the front surface of the cross member reinforcement 120 in the vehicle body front-rear direction and extending in the vehicle width direction. Therefore, the sub-frame cross member 90 and the front side frame coupling portion 56a are not provided in the rear sub-frame 50 of the second embodiment.

The frame member 122 is formed in a substantially U-shaped cross section and joined to the front surface of the cross member reinforcement 120, whereby the upper side cross member 53 is formed in a substantially quadrangular closed cross section extending in the vehicle width direction (see FIG. 23).

The connecting brackets 124 are joined to both ends of the upper cross member portion 53 in the vehicle width direction. The coupling bracket 124 is composed of a first bracket 125 and a second bracket 126. The first bracket 125 is formed in an inverted L-shape in cross section in front view of the vehicle body, and has a vertical surface portion 125a extending vertically and a lateral surface portion 125b extending outward in the vehicle width direction from an upper end of the vertical surface portion 125 a. The first bracket 125 is joined to the frame member 122 and the cross member reinforcement 120 in a state where the longitudinal surface portion 124a and the lateral surface portion 124b are in contact with the cutout portion formed at the end portion of the frame member 122. On the other hand, the second bracket 126 is formed in an inverted U-shape in cross section in front view of the vehicle body, having an upper surface portion 126a extending in the vehicle body front-rear direction along the lower surface portion 2a of the rear side member 2, and a pair of left and right side surface portions 126b extending vertically downward from both ends of the upper surface portion 126a in the vehicle width direction. The second bracket 126 is provided above the first bracket 125 so that the side surface portions 126b and the lateral surface portion 125b of the first bracket 125 sandwich the end portion 122a of the frame member 122, and is joined to the lateral surface portion 125b of the first bracket 125, the frame member 122, and the cross member reinforcement 120.

The upper side member section 53 is connected to the rear side member 2 via connecting brackets 124 at both ends in the vehicle width direction. Specifically, the upper surface portion 126a of the second bracket 126 and the lower surface portion 2a of the rear side member 2 are fastened by a bolt B6 and a nut not shown, and the lateral surface portion 125B of the first bracket 125 and the lower surface portion 2a of the rear side member 2 are fastened by a bolt B7 and a nut not shown. Further, a tubular member 128 is provided between the lateral surface portion 125B of the first bracket 125 and the upper surface portion 126a of the second bracket 126 in a state of penetrating the vehicle frame member 122, and a bolt B7 for fastening the first bracket 125 and the rear side member 2 is screwed to a nut fixed to the rear side member 2 through the tubular member 128.

In the second embodiment, as shown in fig. 21, the front side load absorbing portion 54a is formed in a shape in which the dimension in the vertical direction gradually increases from the rear side to the front side in the vehicle body longitudinal direction, and a flange portion 129 is provided at the front end portion. In the second embodiment, the flange portion 129 is fastened to the beam reinforcement 120 by bolts and nuts not shown, and thereby the front side load absorbing portion 54a is coupled to the upper side beam portion 53.

In the first embodiment described above, the rear subframe 50 is provided with: an upper frame portion 52 connected to the front sides of the left and right front frame connecting portions 56a, respectively, and extending in the vehicle body longitudinal direction; a branch frame member 61 coupled to the upper frame portion 52; and a lower frame member 71 extending from the branch frame member 61 toward the front side of the vehicle body in a substantially horizontal direction. However, in the second embodiment, the upper frame portion 52 and the branch frame members 61 are not provided in the rear subframe 50, and the lower frame member 71 extends directly from the upper cross member portion 53 toward the vehicle body front side in the distal direction.

The lower frame member 71 includes: a rear portion 711 extending from the upper side beam portion 53 toward the vehicle body front side and lower side; an intermediate portion 712 extending from a front end of the rear portion 711 toward the front side and the lower side of the vehicle body at a larger angle with respect to the horizontal plane than the lower frame member 711; and a front portion 713 extending substantially horizontally from a front end of the intermediate portion 712 toward the vehicle body front side.

In the first embodiment, the lower frame member 71 is formed in a vertically flat shape and is formed in a predetermined region on the vehicle body front side so that the lateral width (dimension in the vehicle width direction) increases toward the vehicle body front side. However, in the second embodiment, as shown in fig. 20 and 21, the lower frame member 71 is formed in a closed cross-sectional shape having a cross-sectional quadrilateral shape in which the lateral width (the dimension in the vehicle width direction) is substantially larger than the dimension in the vertical direction, and the cross-sectional width is substantially equal over the entire region in the front-rear direction. The front portion 713 of the lower frame member 71 is formed such that the vertical dimension thereof increases from the rear side of the vehicle body to the front side. Specifically, the lower surface of the lower frame member 71 is a substantially horizontal surface, and the upper surface is formed to be higher and lower as extending from the vehicle body rear side to the front side with reference to the lower surface.

As shown in fig. 22, the lower frame member 71 includes flanges 130, 132 (a front flange 130 and a rear flange 132) for connection at the front end and the rear end in the vehicle body longitudinal direction. As shown in fig. 24, the front flange 130 is formed in an L-shaped cross section that abuts the rear and lower surfaces of the battery frame 30, more specifically, the rear and lower surfaces of the rear beam 31, and is fixed to the battery frame 30 by a bolt B8 and a nut N8 fixed in the rear beam 31. Thereby, the front end of the lower frame member 71 is coupled to the battery frame 30.

On the other hand, the rear flange 132 is formed in a shape along the front surfaces of the frame member 122 and the beam reinforcement 120 of the upper side beam portion 53, and is fixed to the upper side beam portion 53 by a bolt B9, a nut N9 fixed to the inside of the upper side beam portion 53 (frame member 122), a bolt B10, and a nut N10 fixed to the rear surface of the beam reinforcement 120, as shown in fig. 23. Thereby, the rear end of the lower frame member 71 is connected to the upper cross member portion 53.

The rear vehicle body structure according to the second embodiment differs from the rear vehicle body structure according to the first embodiment as described above, but basically the same operational effects as those of the first embodiment can be obtained.

That is, when a rear collision occurs and a collision load acts from the rear of the vehicle body, the load absorbing portion 6 provided in the rear side frame 2 starts buckling deformation, and then the collision load is also input to the rear subframe 50, so that the load absorbing portion 54 provided in the rear subframe 50 buckles and deforms to absorb the collision load. In the rear subframe 50, after the rear side load absorbing portion 54b is buckled and deformed, the front side load absorbing portion 54a is buckled and deformed to absorb the collision load.

The load input to the rear subframe 50 is transmitted from the upper side cross member portion 53 of the rear subframe 50 to the rear side member 2 via the connecting bracket 124 to be transmitted to the vehicle body front side, and is transmitted from the upper side cross member portion 53 of the rear subframe 50 to the battery frame 30 via the lower side frame member 71. Therefore, the load input to the rear subframe 50 can be dispersed to the vehicle upper side and the vehicle lower side on the vehicle front side, and the deformation of the rear subframe 50 can be suppressed. In the case where the attachment 40, 44, 45 is provided at the vehicle body rear portion and at the vehicle body front side with respect to the rear end portion of the rear subframe 50, the attachment 40, 44, 45 provided at the vehicle body rear portion can be protected, and the safety of the occupant in the vehicle compartment can be improved.

Although the present embodiment has been described with respect to a vehicle such as an electric vehicle in which the range extending device 40 is provided at the rear portion of the vehicle body, the present invention is similarly applicable to a vehicle in which a fuel tank, an electric storage device, and other accessories are provided at the rear portion of the vehicle body as important safety components, as well as to other vehicles such as an electric vehicle.

The present invention is not limited to the illustrated embodiments, and various modifications and design changes may be made without departing from the scope of the present invention.

The invention described above is summarized as follows.

The rear vehicle body structure of a vehicle of the present invention includes: a rear side member extending in the front-rear direction of the vehicle body at the rear of the vehicle body; the rear auxiliary frame is arranged below the rear longitudinal beam and extends along the front-rear direction of the vehicle body; the rear subframe includes a front side load absorbing portion and a rear side load absorbing portion that extend toward the vehicle body rear side with respect to an important safety member provided at the vehicle body rear portion and are located at the vehicle body rear side with respect to the important safety member, the front side load absorbing portion and the rear side load absorbing portion absorbing a collision load from the vehicle body rear side when the collision load acts, the rear side load absorbing portion being provided at the vehicle body rear side of the front side load absorbing portion, and an axial compression strength of the rear side load absorbing portion being set lower than that of the front side load absorbing portion.

According to this configuration, the rear subframe disposed below the rear side member includes the front side load absorbing portion and the rear side load absorbing portion that extend toward the vehicle body rear side with respect to the important safety member disposed at the vehicle body rear portion and are located at the vehicle body rear side with respect to the important safety member, and the axial compression strength of the rear side load absorbing portion is set lower than that of the front side load absorbing portion.

Accordingly, the rear sub-frame can be deformed to buckle the rear load absorbing portion away from the important safety member and then deform to buckle the front load absorbing portion at the time of a rear collision, so that the rear sub-frame can absorb the collision load in this order of the rear load absorbing portion and the front load absorbing portion at the time of a rear collision, and the important safety member provided at the rear portion of the vehicle body can be protected by the rear sub-frame. In addition, in the event of a rear collision, the rear sub-frame can improve the safety of the occupant in the vehicle interior by absorbing the collision load in the order of the rear side load absorbing portion and the front side load absorbing portion of the rear sub-frame.

In the above rear vehicle body structure of the vehicle, the rear subframe includes a frame connecting portion that is provided between the front side load absorbing portion and the rear side load absorbing portion, that is connected to the front side load absorbing portion and the rear side load absorbing portion, and that is connected to the rear side member.

According to this structure, the rear subframe includes a frame connecting portion that is provided between the front side load absorbing portion and the rear side load absorbing portion, is connected to the front side load absorbing portion and the rear side load absorbing portion, and is connected to the rear side member. Accordingly, the front side load absorbing portion and the rear side load absorbing portion are coupled to the frame coupling portion coupled to the rear side member, and therefore, as compared with a case where the front side load absorbing portion and the rear side load absorbing portion are integrally formed, the bending rigidity can be improved, and the rear side load absorbing portion and the front side load absorbing portion can be effectively buckled and deformed at the time of a rear collision.

In the above-described rear vehicle body structure of the vehicle, each of the front side load absorbing portion and the rear side load absorbing portion has a closed cross-section portion formed in a closed cross-section in a cross-section orthogonal to the vehicle longitudinal direction, the frame connecting portion has a load transmitting portion extending in the vehicle longitudinal direction, the load transmitting portion transmits a collision load from the front side load absorbing portion to the rear side load absorbing portion when the collision load acts from the vehicle rear side, and the load transmitting portion is formed in a closed cross-section identical to the closed cross-section portion of the front side load absorbing portion and the closed cross-section portion of the rear side load absorbing portion in the cross-section orthogonal to the vehicle longitudinal direction.

According to this configuration, the frame connecting portion has a load transmitting portion extending in the vehicle body longitudinal direction, and the load transmitting portion is formed in the same closed cross-sectional shape as the closed cross-sectional portions of the front side load absorbing portion and the rear side load absorbing portion. Therefore, at the time of a rear collision, the collision load can be efficiently transmitted from the rear side load absorbing portion to the front side load absorbing portion. In addition, as compared with the case where the front side load absorbing portion and the rear side load absorbing portion are formed in a cross-sectional shape different from the closed cross-sectional shape of the front side load absorbing portion and the rear side load absorbing portion, the bending rigidity can be improved, and the rear side load absorbing portion and the front side load absorbing portion can be effectively buckled and deformed at the time of a rear collision.

In the above-described rear vehicle body structure of the vehicle, the closed cross-section portion of the front side load absorbing portion, the closed cross-section portion of the rear side load absorbing portion, and the load transmitting portion of the frame connecting portion are formed in a cross-sectional polygonal shape having more sides than a cross-sectional quadrilateral shape, the frame connecting portion includes a peripheral wall portion formed in a closed cross-section shape on an orthogonal cross-section orthogonal to the vehicle width direction, and is formed in such a manner that: in the peripheral wall portion, a vehicle body front side of the load transmission portion is butted joined to a vehicle body front side of the peripheral wall portion, and a vehicle body rear side of the load transmission portion is butted joined to a vehicle body rear side of the peripheral wall portion.

According to this configuration, the closed cross-section portion of the front side load absorbing portion, the closed cross-section portion of the rear side load absorbing portion, and the load transmitting portion of the frame connecting portion are formed in the cross-sectional polygonal shape having a larger number of sides than the cross-sectional quadrilateral shape, whereby more ridges can be provided than in the case of the cross-sectional quadrilateral shape, the axial compression strength can be improved, and the above-described effects can be obtained more effectively.

Further, if the load transmission portion is joined to the peripheral wall portion by the flange portions provided at the vehicle body front side end portion and the vehicle body rear side end portion thereof, respectively, during a rear collision, stress concentration occurs at portions other than the flange portions of the vehicle body front side end portion and the vehicle body rear side end portion of the load transmission portion, and deformation occurs, which may cause failure in effective absorption of the collision load. However, according to the above configuration, since the vehicle body front side of the load transmission portion is butted against the vehicle body front side of the peripheral wall portion, and the vehicle body rear side of the load transmission portion is butted against the vehicle body rear side of the peripheral wall portion, it is possible to suppress the occurrence of stress concentration, and at the time of a rear collision, it is possible to effectively absorb the collision load by the front side load absorbing portion and the rear side load absorbing portion.

In the rear vehicle body structure of the vehicle described above, the attachment other than the important safety component is provided at a position overlapping the front side load absorbing portion in the vehicle body front-rear direction.

According to this configuration, since the attachment other than the important safety member is provided at the position overlapping the front side load absorbing portion in the vehicle body front-rear direction, the important safety member can be protected at the time of a rear collision, and the attachment provided at the position overlapping the front side load absorbing portion in the vehicle body front-rear direction can be prevented from being damaged at the time of buckling deformation of only the rear side load absorbing portion.

In the above rear vehicle body structure of the vehicle, the rear subframe includes a cross member portion having a closed cross section, the cross member portion extending in the vehicle width direction below the rear side member at a position on the vehicle body rear side of the important safety member, and both end portions are connected to the rear side member, and the front end portion of the front side load absorbing portion is connected to the cross member portion.

According to this structure, the front side load absorbing portion and the rear side load absorbing portion can be favorably buckled and deformed while receiving a load by the cross member connected to the rear subframe. Therefore, important safety members provided at the rear portion of the vehicle body can be well protected by the rear subframe.

Industrial applicability

As described above, according to the present invention, in a vehicle provided with a rear subframe disposed below a rear side member, it is possible to absorb a collision load at the time of a rear collision to protect important safety members and to improve the safety of occupants in a vehicle cabin, and therefore, the present invention has excellent applicability in the field of manufacturing of such vehicles.