JP2005231477A - Vehicle body rear part structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make compatible the enhancement of absorption performance of collision energy at rear collision at high speed and the prevention of deformation of a rear side member at rear collision at low speed. <P>SOLUTION: The vehicle body rear part structure is constituted such that ribs 30 as an axial compression rigidity change means for reducing axial compression rigidity of the outer side 12G in a vehicle width direction of the rear side member 12 than axial compression rigidity of the inner side 12H in the vehicle width direction are formed at a further rear portion 12F than a second rear cross member 22, i.e., a rear portion of an arrangement position of a fuel tank in the left and right rear side members 12 respectively. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a vehicle body rear structure, and more particularly to a vehicle body rear structure that absorbs an impact at the time of a collision in a vehicle body such as an automobile.

2. Description of the Related Art Conventionally, in a vehicle body rear structure that absorbs an impact at the time of a collision in a vehicle body such as an automobile, a means for lowering the rigidity toward the front of the vehicle body is provided at a position behind the rear suspension cross member of the rear side member (also referred to as a rear frame). The rear side member is deformed at the time of rear impact to absorb impact energy, and a means for increasing the rigidity against a collision in the front of the vehicle body is provided at the bent portion of the rear side member, and the vehicle body is positioned at a position corresponding to the silencer of the rear suspension cross member. There is known a configuration that prevents a fuel tank from being damaged at the time of a rear collision by providing means for increasing rigidity against a forward collision (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 4-303074

  However, in Patent Document 1, the axial compression rigidity of the entire cross section is lowered at a position rearward of the rear suspension cross member of the rear side member. As a result, the rear side member is deformed even at a low speed rear collision. For this reason, it is impossible to achieve both the improvement of the collision energy absorption performance at the high speed rear collision and the prevention of the deformation of the rear side member at the low speed rear collision.

  In view of the above facts, an object of the present invention is to provide a vehicle body rear structure that can achieve both improvement in impact energy absorption performance at a high speed rear collision and prevention of deformation of a rear side member at a low speed rear collision.

The vehicle body rear structure according to the first aspect of the present invention includes a rear side member disposed along the vehicle longitudinal direction at both ends in the vehicle width direction of the vehicle rear portion,
An axial compression stiffness changing means disposed at a rear portion of the fuel tank arrangement position in the rear side member, and lowering the axial compression stiffness of the rear side member in the vehicle width direction outside the axial compression stiffness in the vehicle width direction;
A rear bumper reinforcement attached to a rear end portion of the rear side member, wherein an attachment portion to the rear side member is inclined from the vehicle body rear side to the vehicle body front side from the vehicle width direction inner side to the vehicle width direction outer side of the rear side member. When,
It is characterized by having.

  Therefore, in a high-speed rear impact, when the rear side member is deformed by a load from the rear bumper reinforcement, the rear side member is changed by the axial compression rigidity changing means disposed at the rear portion of the fuel tank arrangement position in the rear side member. Since the axial compression rigidity on the outer side in the vehicle width direction of the member is lower than the axial compression rigidity on the inner side in the vehicle width direction, the rear side member of the rear side member is bent inward in the vehicle width direction. As a result, it is possible to improve the collision energy absorption performance in the high-speed rear impact. For this reason, a fuel tank can be protected. On the other hand, in a low-speed rear collision, the rear bumper reinforcement attached to the rear end of the rear side member is attached to the rear side member from the vehicle width direction inner side to the vehicle width direction outer side of the rear side member. Since the vehicle is tilted forward, the load from the rear bumper reinforcement is applied to the inner side in the vehicle width direction of the rear side member compared to the outer side in the vehicle width direction of the rear side member through the mounting portion of the inclined rear bumper reinforcement to the rear side member. It works a lot. As a result, the load from the rear bumper reinforcement can be supported on the inner side in the vehicle width direction of the rear side member having higher axial compression rigidity than the outer side in the vehicle width direction of the rear side member. For this reason, it is possible to prevent the rear side member from being deformed in a low-speed rear collision.

  The vehicle body rear structure according to the first aspect of the present invention is arranged at the rear side member disposed along the vehicle body longitudinal direction at both ends in the vehicle width direction of the rear portion of the vehicle body, and at the rear portion of the fuel tank arrangement position on the rear side member. Shaft compression rigidity changing means for lowering the axial compression rigidity of the rear side member in the vehicle width direction outside the axial compression rigidity of the inner side in the vehicle width direction, and a rear side member attached to the rear end of the rear side member. The rear side member has a rear bumper reinforcement that is inclined from the rear side of the vehicle body toward the outer side of the vehicle width direction from the inner side in the vehicle width direction to the outer side in the vehicle width direction. It has an excellent effect of being able to achieve both deformation prevention of the rear side member at the rear impact.

  An embodiment of a vehicle body rear structure according to the present invention will be described with reference to FIGS.

  In the figure, the arrow UP indicates the vehicle body upward direction, the arrow FR in the figure indicates the vehicle body front direction, and the arrow IN in the figure indicates the vehicle width inside direction.

  As shown in FIG. 1, rear side members 12 are disposed along the longitudinal direction of the vehicle body at both ends in the vehicle width direction at the rear of the vehicle body 10 of the present embodiment. Further, rear bumper reinforcements 14 of rear bumpers are installed at the rear end portions 12A of the left and right rear side members 12, and a collision load input to the rear bumper reinforcement 14 when the vehicle body 10 undergoes a rear collision (rear collision). Is received by the left and right rear side members 12.

  As shown in FIG. 4, the rear part of the rear side member 12 is a crash box 12B, and the crash box 12B is axially deformed in the longitudinal direction of the vehicle body at the initial stage of the collision.

  As shown in FIG. 1, a fuel tank 16 is disposed between the front portions 12 </ b> C of the left and right rear side members 12. Further, the front end portions 12D of the left and right rear side members 12 are respectively connected to the rear portion 18A of the rocker 18, and the first rear cross member 20 is installed on the front end portions 12D of the left and right rear side members 12. In addition, a second rear cross member 22 is installed in a substantially central portion 12E in the front-rear direction of the left and right rear side members 12, and the fuel tank 16 is connected to the first rear cross member 20 and the second rear member by a fixing member 26 such as a bolt. The rear cross member 22 is fixed to the lower surface side.

  An axial compression rigidity (rear collision) of the outer side 12G of the rear side member 12 in the vehicle width direction is provided at a rear portion 12F of the rear side member 12 behind the second rear cross member 22 which is a rear portion of the fuel tank arrangement positions 12C and 12D. Ribs 30 are formed as shaft compression rigidity changing means for lowering the rigidity of the vehicle body in the vehicle width direction on the inner side 12H in the vehicle width direction.

  In the present embodiment, the rib 30 is formed at a substantially central portion in the front-rear direction of the portion 12F of the rear side member 12.

  As shown in FIG. 3, the cross-sectional shape of the portion 12F of the rear side member 12 viewed from the front-rear direction of the vehicle body is a hat shape with the opening directed upward of the vehicle body. The flange 12J formed at the opening end of the rear side member 12 is coupled to the lower surface 32A of the floor panel 32, and the rear side member 12 forms a closed cross-sectional structure 34 that extends in the vehicle longitudinal direction with the floor panel 32.

  The rib 30 is formed in the vehicle body vertical direction on the wall portion of the rear side member 12 on the vehicle width direction outer side 12G, and the lower end portion 30A of the rib 30 reaches the lower wall portion 12K of the rear side member 12. The upper wall portion 30B of 30 reaches the vicinity of the flange 12J.

  Therefore, as shown in FIG. 2, when the vehicle body 10 collides with the collision body K at a high speed, that is, when the collision body K collides with the vehicle body 10 from the rear of the vehicle body (in the direction of arrow A) at a high speed. When the rear side member 12 is deformed by a load from the ment 14, a shaft 30 on the outer side 12 </ b> G in the vehicle width direction of the rear side member 12 is formed by the rib 30 disposed in the portion 12 </ b> F behind the fuel tank disposed position in the rear side member 12. Since the compression rigidity is lower than the axial compression rigidity of the vehicle width direction inner side 12H, the portion 12F of the rear side member 12 is bent inward in the vehicle width direction.

  As shown in FIG. 1, the rear bumper reinforcement 14 has an arc shape that bulges to the rear side of the vehicle body in a plan view.

  As shown in FIG. 5, the outer end portion of the rear bumper reinforcement 14 in the vehicle width direction is an attachment portion 14A for the rear side member 12 to the crash box 12B, and the attachment portion 14A of the rear bumper reinforcement 14 is the rear side member 12. The vehicle is inclined in an arc from the vehicle rear side toward the vehicle front side from the vehicle width direction inner side 12H toward the vehicle width direction outer side 12G.

  Therefore, as shown in FIG. 6, when the vehicle body 10 collides with the collision body K at a low speed, that is, when the collision body K collides with the vehicle body 10 from the rear (arrow A direction) at a low speed, the rear bumper reinforcements. The load F from the ment 14 acts more on the inner side 12H of the rear side member 12 than on the outer side 12G of the rear side member 12 through the attachment portion 14A of the inclined rear bumper reinforcement 14 to the rear side member 12. It is supposed to do.

  That is, in this embodiment, as shown in FIG. 7, the distribution of the buckling load of the rear side member 12 is such that the buckling load G1 of the crash box 12B <the buckling load G2 of the portion 12F behind the fuel tank installation position <the fuel. It is the buckling load G3 at the tank arrangement positions 12C and 12D.

  Next, the operation of this embodiment will be described.

  In the present embodiment, as shown in FIG. 2, when the rear body member 12 is deformed by the load from the rear bumper reinforcement 14 when the vehicle body 10 rearwardly collides with the collision body K, the rear side member 12 The axial compression rigidity of the rear side member 12 on the outer side 12G in the vehicle width direction is lower than the axial compression rigidity on the inner side 12H in the vehicle width direction due to the ribs 30 arranged at the rear portion 12F of the fuel tank arrangement position. The part 12F of the member 12 is bent inward in the vehicle width direction.

  As a result, it is possible to improve the performance of absorbing the collision energy at the rear of the vehicle body at a high speed rear collision. For this reason, the deformation | transformation of the site | part which has arrange | positioned the fuel tank 16 of a vehicle body rear part can be suppressed, and the fuel tank 16 can be protected.

  On the other hand, as shown in FIG. 6, when the vehicle body 10 collides rearward with the collision body K at a low speed, the load F from the rear bumper reinforcement 14 is attached to the rear side member 12 of the inclined rear bumper reinforcement 14. Therefore, the rear side member 12 acts more on the vehicle width direction inner side 12H than the rear side member 12 on the vehicle width direction outer side 12G.

  As a result, the load from the rear bumper reinforcement 14 can be supported on the vehicle width direction inner side 12H of the rear side member 12 having higher axial compression rigidity than the vehicle width direction outer side 12G of the rear side member 12. For this reason, although the crash box 12B is deformed at a low-speed rear collision, the deformation of the main body of the rear side member 12 excluding the crash box 12B can be prevented, so that repair or replacement of the main body of the rear side member 12 can be avoided.

  Therefore, the vehicle body rear structure of the present embodiment can achieve both improvement in the performance of absorbing the collision energy at the high-speed rear collision and prevention of deformation of the rear side member at the low-speed rear collision.

  Although the present invention has been described in detail with respect to specific embodiments, the present invention is not limited to the above-described embodiments, and various other embodiments are possible within the scope of the present invention. It will be apparent to those skilled in the art. For example, in the above embodiment, the rear bumper reinforcement 14 has an arc shape that bulges to the rear side of the vehicle body in a plan view. However, the plan view shape of the rear bumper reinforcement 14 is not limited to this, and the vehicle width direction of the rear side member 12 is not limited thereto. Any other shape may be used as long as it is inclined from the inner side 12H toward the outer side 12G in the vehicle width direction toward the front side of the vehicle body, and the mounting portion 14A of the rear bumper reinforcement 14 is provided with the rear side member 12 as shown in FIG. The vehicle 14 is inclined linearly from the rear side of the vehicle body to the front side of the vehicle body from the vehicle width direction inner side 12H to the vehicle width direction outer side 12G, and a portion 14B between the mounting portions 14A in the rear bumper reinforcement 14 extends in the vehicle width direction. It is good also as the extended linear shape.

  Further, in the above embodiment, the axial compression stiffness that lowers the axial compression stiffness of the rear side member 12 in the vehicle width direction outer side 12G to the rear side member 12 lower than the axial compression stiffness of the rear side member 12 in the vehicle width direction inner side 12H. Although the rib 30 as the changing means is formed, the shaft compression rigidity changing means is not limited to the rib 30. For example, as shown in FIG. 9, the reinforce having the L-shaped cross section on the inner side 12H of the rear side member 12 in the vehicle width direction. It is good also as a structure which has arranged thement 50 along the vehicle body front-back direction.

  Further, in place of the rib 30, other axial compression rigidity changing means such as a thin portion and a slit may be formed on the outer side 12G of the rear side member 12 in the vehicle width direction.

  Further, when the buckling load G2 of the portion 12F behind the fuel tank arrangement position> the buckling load G3 of the fuel tank arrangement positions 12C and 12D, as shown in FIG. 10, the height H of the rib 30 is increased. By doing so, the buckling load G2 of the portion 12F behind the fuel tank arrangement position may be smaller than the buckling load G3 of the fuel tank arrangement positions 12C and 12D.

  Further, by using both the rib 30 and the reinforcement 50, the axial compression rigidity of the outer side 12G in the vehicle width direction of the rear side member 12 at the rear side of the fuel tank arrangement position in the rear side member 12 is set to the inner side 12H in the vehicle width direction. It is good also as a structure made to fall rather than axial compression rigidity.

It is a schematic plan view which shows the vehicle body rear part structure which concerns on one Embodiment of this invention. It is a schematic plan view showing a state at the time of a rear collision showing a vehicle body rear part structure according to an embodiment of the present invention. FIG. 3 is an enlarged cross-sectional view taken along line 3-3 in FIG. 1. It is the perspective view seen from the vehicle body slant front inner side which shows the principal part of the vehicle body rear part structure which concerns on one Embodiment of this invention. 1 is a schematic plan view showing an end portion in a vehicle width direction of a rear bumper reinforcement of a vehicle body rear structure according to an embodiment of the present invention. It is a schematic plan view showing a state at the time of a rear collision at an end portion in the vehicle width direction of a rear bumper reinforcement having a vehicle body rear portion structure according to an embodiment of the present invention. It is a figure which shows distribution of the buckling load in the rear side member of the vehicle body rear part structure which concerns on one Embodiment of this invention. It is a schematic plan view which shows the vehicle body rear part structure which concerns on other embodiment of this invention. It is sectional drawing corresponding to FIG. 3 which shows the vehicle body rear part structure which concerns on other embodiment of this invention. It is sectional drawing corresponding to FIG. 3 which shows the vehicle body rear part structure which concerns on other embodiment of this invention.

Explanation of symbols

10 Auto Body 12 Rear Side Member 12A Rear Side Member Rear End 12B Crash Box 12C Rear Side Member Front (Fuel Tank Arrangement Position)
12D Front end of rear side member (position of fuel tank)
12F Rear part of fuel tank arrangement position in rear side member 12G Rear side member vehicle width direction outer side 12H Rear side member vehicle width direction inner side 14 Rear bumper reinforcement 14A Rear bumper reinforcement attachment part 16 Fuel tank 30 Rib (Axial compression rigidity change) means)
50 Reinforcement (shaft compression stiffness changing means)

Claims (1)

A rear side member disposed along the longitudinal direction of the vehicle body at both ends in the vehicle width direction at the rear of the vehicle body;
An axial compression stiffness changing means disposed at a rear portion of the fuel tank arrangement position in the rear side member, and lowering the axial compression stiffness of the rear side member in the vehicle width direction outside the axial compression stiffness in the vehicle width direction;
A rear bumper reinforcement attached to a rear end portion of the rear side member, wherein an attachment portion to the rear side member is inclined from the vehicle body rear side to the vehicle body front side from the vehicle width direction inner side to the vehicle width direction outer side of the rear side member. When,
A vehicle body rear structure characterized by comprising:

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