Vehicle body structure

A vehicle body structure may include: two first rear side members respectively provided on opposite sides of a rear floor; a rear sub-frame including a front cross member and a rear cross member spaced apart from each other, where opposite ends of the front cross member and opposite ends of the rear cross member are coupled to two of the first rear side members, respectively; a vehicle body cross member which is spaced rearward from the rear sub-frame, connected to the first rear side members, and fixed to the rear floor; two second rear side members provided between two of the first rear side members, and arranged side by side with each of two of the first rear side members; and two truss members each extending from first connecting portions to second connecting portions, respectively.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of Korean Patent Application No. 10-2018-0154970, filed on Dec. 5, 2018, the entire contents of which are incorporated herein by reference.

FIELD

The present disclosure relates to a vehicle body structure for effectively dispersing a collision load of the vehicle.

BACKGROUND

Hybrid electric vehicles (HEVs) and plug-in hybrid electric vehicles (PHEVs) have a fuel tank and high-voltage battery components for drive systems. The fuel tank and high voltage battery components are mounted on a rear floor of a vehicle body structure.

In such vehicles, since the fuel tank and the high-voltage battery components are installed on the rear floor, loads acting on the rear floor and rear side members increase. In addition, in such vehicles, a crumple zone of the collision energy for rearward collision decreases accordingly.

The vehicle body structure of such vehicles uses a similar form to the structure of a conventional internal combustion engine vehicle to protect rear components such as a fuel tank, a high-voltage battery, and the like, and at the same time includes collision reinforcement members installed inside the rear side members to enhance rigidity against rearward collision.

However, we have discovered that since the collision reinforcement members are locally excessively applied to the vehicle body structure of such vehicles, there is a problem that the manufacturing cost and the weight increase. In addition, although the rigidity of the rear side members is high because the collision reinforcement members are installed inside the rear side members, the rigidity of the regions where the rear side members are not located (e.g., a rear center portion, etc.) is low. Therefore, we found that it is difficult to protect the components mounted on the rear floor when a collision load is applied to the regions where the rear side members are not located.

SUMMARY

The present disclosure provides a vehicle body structure capable of stably protecting components mounted on a rear floor by effectively dispersing a collision load from a rear side of the vehicle.

In accordance with an aspect of the present disclosure, a vehicle body structure defining a longitudinal direction, the vehicle body structure may include: two first rear side members provided on opposite sides of a rear floor and configured to respectively extend in the longitudinal direction; a rear sub-frame including a front cross member and a rear cross member spaced apart from each other, wherein opposite ends of the front cross member are respectively coupled to a corresponding first rear side member among the two first rear side members, and opposite ends of the rear cross member are respectively coupled to the corresponding first rear side member among the two the first rear side members; a vehicle body cross member spaced apart from the rear sub-frame and fixed to the rear floor, wherein opposite ends of the vehicle body cross member are respectively connected to the corresponding the first rear side member among the two first rear side members; two second rear side members provided between the two first rear side members on the rear floor, and arranged side by side with each of the two first rear side members so as to be spaced apart from each other, wherein the two second rear side members respectively extend from a rear end of the rear floor to the vehicle body cross member, and wherein the vehicle body cross member and the two second rear side members are respectively connected to each other at first connecting portions, and opposite ends of the rear cross member and the two first rear side members are respectively connected to each other at second connecting portions; and two truss members respectively extending from the first connecting portions to the second connecting portions.

The first connecting portions, the second connecting portions, and third connecting portions are arranged in a triangular shape, wherein the opposite ends of the vehicle body cross member are connected to the first rear side members at the third connecting portions.

The rear cross member of the rear sub-frame may include an intermediate extending portion extending in a vehicle width direction, and two lateral extending portions respectively extending obliquely rearward from opposite ends of the intermediate extending portion to be connected to the second connecting portions.

A lateral load applied to the second connecting portions from a side of the vehicle may be dispersed and transmitted to the corresponding lateral extending portion and the truss members.

A longitudinal load applied to the first rear side members from the rear of the vehicle may be dispersed and transmitted from the third connecting portions to the second connecting portions and the first connecting portions, and a longitudinal load applied to the second rear side members from the rear of the vehicle may be dispersed and transmitted from the first connecting portions to the opposite ends of the vehicle body cross member and the corresponding truss member.

The vehicle body structure may further include first crush boxes connecting rear ends of two of the first rear side members and a rear bumper structure.

The vehicle body structure may further include second crush boxes connecting rear ends of two of the second rear side members and the rear bumper structure.

The truss member may include an outer member connecting the corresponding first connecting portion and the corresponding second connecting portion, and an inner member provided inside the outer member to reinforce rigidity.

DETAILED DESCRIPTION

The following forms are provided to fully convey the spirit of the present disclosure to a person having ordinary skill in the art to which the present disclosure belongs, and the present disclosure is not limited thereto, but may be embodied in other forms. In order to clarify the present disclosure, it is possible to omit the parts of the drawings that are not related to the description, and the size of the components may be slightly exaggerated to facilitate understanding.

As illustrated inFIGS. 1 and 2, a vehicle body structure according to one form of the present disclosure includes: two first rear side members10, two second rear side members20, a rear sub-frame30, a vehicle body cross member40, and two truss members50.

The two first rear side members10are provided on opposite sides of a rear floor1so as to extend in a longitudinal direction, respectively. Opposite ends of the rear sub-frame30are respectively coupled to the corresponding first rear side member among the two first rear side members10so as to reinforce the rigidity of rear suspension mounting portions60provided on the opposite sides of the rear floor1.

The rear sub-frame30includes a front cross member31and a rear cross member32spaced apart from each other in a front-rear direction. Opposite ends of the front cross member31are respectively coupled to the two first rear side members10, and opposite ends of the rear cross member32are coupled to two of the first rear side members10, respectively. The rear sub-frame30may reinforce a lateral rigidity of the rear floor1to protect components such as a fuel tank70and a battery (not shown) mounted on the rear floor1.

The vehicle body cross member40is spaced apart from the rear sub-frame30in a rearward direction by a predetermined distance, and opposite ends of the vehicle body cross member40are connected to two of the first rear side members10, respectively. The vehicle body cross member40is not only fixed to the rear floor1in an integrated form so as to reinforce the lateral rigidity of the rear floor1together with the rear sub-frame30, but also serves to protect the fuel tank70, the battery, and the like, which are mounted on the front of the vehicle body cross member40, from rearward collision.

Two of the second rear side members20are provided between two of the first rear side members10at the rear of the vehicle body cross member40, and each of two of the second rear side members20is arranged side by side (almost in parallel) with each of two of the first rear side members10so as to be laterally spaced apart from each other. Each of the second rear side members20extends from the rear end of the rear floor1to the vehicle body cross member40and is fixed to the rear floor1in an integrated state.

In one form, as illustrated inFIG. 1, the two truss members50are respectively extended from first connection portions81to second connecting portions82. At the first connecting portions81, the vehicle body cross member40and two of the second rear side members20are connected, and opposite ends of the rear cross member32and the two first rear side members10are connected to each other at the corresponding second connecting portions82.

In another form, as illustrated inFIG. 3, the vehicle body structure is configured that the first connecting portions81, the second connecting portions82, and third connecting portions83are arranged in a triangular shape. At the third connecting portions83, the opposite ends of the vehicle body cross member40and the first rear side members10are connected. Such vehicle body structure may reinforce the lateral and longitudinal rigidity of a front region A (fuel tank mounting region) of the vehicle body cross member40. In addition, the vehicle body structure may safely protect the front region A of the vehicle body cross member40of the rear floor1against collision by dispersing a lateral load P1and a longitudinal load P2applied from a rear side.

Referring toFIGS. 1 to 3, the rear cross member32of the rear sub-frame30includes an intermediate extending portion32aextending in a vehicle width direction, and two of lateral extending portions32bextending obliquely rearward from opposite ends of the intermediate extending portion32ato be connected to the second connecting portions82.

As illustrated inFIG. 3, the lateral load P1applied to the second connecting portions82from a side of the vehicle may be dispersed and transmitted to the lateral extending portions32band the truss members50. A part of the lateral load P1is transmitted to the rear sub-frame30through the lateral extending portions32band the other part of the lateral load P1is transmitted to the vehicle body cross member40through the truss members50. The lateral load P1is widely dispersed and transmitted to the rear side of the rear floor1through the truss members50and the vehicle body cross member40as well as the rear sub-frame30. Thus, the vehicle body structure may safely protect the front region A of the body cross member40from lateral collision.

As illustrated inFIG. 3, in the vehicle body structure, the longitudinal load P2applied to the first rear side members10from the rear of the vehicle is dispersed and transmitted from the third connecting portions83to the second connecting portions82side and the first connecting portions81side, and the longitudinal load P2applied to the second rear side members20from the rear of the vehicle is dispersed and transmitted from the first connecting portions81to the opposite ends of the vehicle body cross member40side and the truss members50side. Accordingly, as illustrated inFIG. 4, the vehicle body structure may safely protect the front region A (fuel tank installation region) of the vehicle body cross member40even when a collision occurs from the rear of the vehicle.

In addition, the vehicle body structure according to the present form may significantly reinforce the rigidity against collision at a rear intermediate portion than in the prior art because the vehicle body structure includes two of the first rear side members10and two of the second rear side members20, and may safely protect the front region A of the vehicle body cross member40because the first rear side members10and the second rear side members20share the load P2applied from the rear of the vehicle. That is, as illustrated inFIGS. 3 and 4, when the rear collision occurs, a rear region B of the vehicle body cross member40is deformed to absorb the impact, but the front region A of the vehicle body cross member40may be maintained without deformation because the load is evenly dispersed.

Referring toFIG. 5, a rear bumper structure90may be connected to the rear ends of two of the first rear side members10by first crush boxes101for absorbing the impact, but as illustrated inFIG. 6, second crush boxes102connecting the rear ends of two of the second rear side members20and the rear bumper structure90may be additionally provided.

When the first crush boxes101and the second crush box102are installed together as in the example ofFIG. 6, it is possible to further increase the impact damping effect on the rear collision, it is possible to increase the tuning freedom of the crush boxes, and it is possible that the crush boxes are made of thin material. In addition, the coupling stability of the rear bumper structure90may also be reinforced.

FIGS. 7A to 7Dillustrate a configuration of the truss member50and processes of installing the truss member50. The truss member50may include an outer member52connecting the first connecting portion81and the second connecting portion82, and an inner member51provided inside the outer member52to reinforce rigidity.

When the truss member50is installed, as inFIG. 7A, one end of the inner member51may be connected to the first rear side member10, and as inFIG. 7B, the outer member52may be mounted on an outer side of the inner member51. After the outer member52is installed, as inFIG. 7C, the vehicle body cross member40and one end of the truss member50may be connected while the vehicle body cross member40is installed, and as inFIG. 7D, the second rear side member20may be connected to the first connecting portion81to which the vehicle body cross member40and the truss member50are connected while the second rear side member20is installed.

As is apparent from the above, the vehicle body structure according to the exemplary forms of the present disclosure can safely protect the front region of the vehicle body cross member on which the fuel tank, the battery, and the like are installed from a lateral collision because a lateral load is widely dispersed and transmitted not only through the rear sub-frame but also through the truss members and the vehicle body cross member.

In addition, the vehicle body structure according to the forms of the present disclosure can significantly reinforce the rigidity against collision at a rear intermediate portion than in the prior art because the vehicle body structure includes two of the first rear side members and two of the second rear side members, and can safely protect the front region of the vehicle body cross member from a rear collision because the first rear side members and the second rear side members share the load applied from the rear of the vehicle and the longitudinal load applied to the second rear side members is dispersed and transmitted to the vehicle body cross member and the truss members.