JP2743555B2 - Rear underbody structure of vehicle - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a vehicle rear underbody structure for transmitting a load from the rear of a vehicle input to a rear floor side member of the vehicle to a rocker panel.

(Prior art)

FIG. 4 shows the structure disclosed in Japanese Utility Model Laid-Open Publication No. 63-43806.
1 shows a rear underbody structure of a conventional vehicle.

A rear floor side member 74 is disposed on the vehicle inner side of the rocker inner panel 72 of the rocker portion 70 along the vehicle front-rear direction. The front side of the rear floor side member 74 is joined to the Rokka inner panel 72. As a result, the closed section of the rocker portion 70 and the closed section of the rear floor side member 74 are joined continuously.

Due to the joint between the rocker portion 70 and the rear floor side member 74, a load from the rear of the vehicle input to the rear floor side member 74 is applied to the rocker portion 70 via the vertical wall portion 76.
And the vibration characteristics are improved.

[Problems to be solved by the invention]

However, the height dimension of the rear floor side member 74 is smaller than the height dimension of the rocker portion 70, so that there is a difference in rigidity between them, and the load concentrates on the joint between the rocker portion 70 and the rear floor side member 74. , The load cannot be reliably transmitted to the rocker part 70, and the rear flow side member 74
May be deformed. For this reason, a strut bar bracket 78 that supports a straddle bar 77 attached to the rear floor side member 74 and a rocker portion 70 are connected by a connecting bracket 80, or a reinforcement 82 is arranged in the rocker portion 70. Although the strength is increased by using the reinforcing member, such a structure is not preferable because the number of parts increases, the number of assembling steps and the weight of the vehicle increase.

SUMMARY OF THE INVENTION In view of the above, the present invention provides a rear underbody for a vehicle capable of efficiently and smoothly transmitting a load from the rear of the vehicle input to the rear floor side member to the rocker panel without increasing the number of assembly steps and the weight of the vehicle. The purpose is to obtain the structure of

[Means for solving the problem]

A rear underbody structure for a vehicle according to the present invention includes a rocker panel disposed at both ends in the width direction of the vehicle, and a vehicle front end of a vehicle inner vertical wall portion that is disposed offset from the rocker panel inside the vehicle. A rear floor side member which is curved outwardly of the vehicle and has a step formed on a lower surface thereof, and a height dimension is enlarged corresponding to the height dimension of the rocker panel and is joined to the rocker panel; and a step of the rear floor side member. And a strap bar bracket joined to the lower surface of the vehicle rearward of the vehicle.

[Action]

According to the present invention, when a load from the rear of the vehicle is input to the rear floor side member, the load is transmitted to the rocker panel via the vertical wall. Here, the rear flow side member is joined to the rocker panel in a state where a step is formed and the height dimension of the rear panel is matched, and a straddle bar bracket is disposed on the lower surface of the step of the rear floor side member. Thus, the load transmitted from the rear to the rear floor side member is efficiently and smoothly transmitted to the rocker panel. For this reason, the load does not concentrate due to a curved point having a low rigidity or a difference in cross-sectional height, and there is no problem that the rear flow side member is deformed. Also,
A strut bar bracket is attached to the lower surface of the rear floor side member. In this strut bar bracket, the lower surface, which is on the rear side of the vehicle with respect to the step of the rear floor side member, is located above the lower surface of the rocker panel. Since it is attached to the protruding portion, the minimum height above the ground can be sufficiently secured.

〔Example〕

FIGS. 1 to 3 show one side of the rear underbody portion 10 of the vehicle according to the present embodiment in the vehicle width direction. At both ends in the vehicle width direction, rocker panels 12 are arranged in the vehicle front-rear direction. The Rokka panel 12 is the Rokka outer 14
And Rotsuka Inner 16. Rotsuka Outer 14
The upper part is bent stepwise, the downwardly extending portion is bent in a curved shape, and the longitudinal section is substantially C-shaped. At the upper end in the longitudinal section, a flange 18A is formed so as to be bent upward of the vehicle, and the distal end at the lower end in the longitudinal section is a flange portion 18B.

On the other hand, the Rokkainna 16 has a substantially U-shaped vertical section. A flange 20A bent upward in the vehicle is formed at the upper end in the longitudinal section, and a flange 20B bent toward the vehicle inward is formed at the lower end in the longitudinal section.
The flanges 20A and 20B correspond to the flanges 18A and 18B of the rocker outer 14, respectively. These flanges 18A and 20A and flanges 18B and 2
0B are respectively joined, and the rocker panel 12 has a closed sectional structure. Further, the rear end of the vehicle of the rotka inner 16 is formed as a joint with the wheel house inner 24.

A rear floor side member 26 is arranged in the vehicle front-rear direction in a state of being offset from the rocker panel 12 to the vehicle inside. This rear floor side member 26
The longitudinal section is substantially U-shaped. The upper end of the vehicle outer vertical die 30 in the longitudinal section direction is a flange portion 30A, and the upper end of the vehicle inner vertical wall 32 is formed with a flange 32A bent at a substantially right angle in the vehicle inward direction. The flange 30A is joined to the vehicle inner surface of the wheel house inner 24. That is, as the flange 30A extends toward the front of the vehicle, it is bent along the bending surface of the wheel house inner 24, and its front end is sandwiched between the rotsker inner 16 and the wheel house inner 24.

Also, the vehicle inner vertical wall portion 32 of the rear floor side member 26
Also, the front part of the vehicle is curved outward of the wheel house inner side 24 and extends to the longitudinal middle part of the rotka inner 16. A flange 34 is formed at the extended front end, and is joined to the Rokka Inner 16.

Between the rocker panels 12 provided at both ends in the vehicle width direction,
A floor pan 60 (see FIG. 2) is suspended. The floor pan 60 forms a floor surface of the vehicle. The floor pan 60 has a step between the center floor and the rear floor, and a vertical wall portion 62 is formed.

The floor pan 60 has a vehicle upper opening of the rear floor side member 26 closed, and the rear floor side member 26 has a closed sectional structure.

The lower surface portion 40 of the rear floor side member 26 is formed with a step portion 42 in which a portion extending toward the front side of the vehicle is bent downward, and the distance between the lower surface portion 40 and the upper surface portion 33 of the floor pan 60 is increased. As a result, the front end of the rear floor side member 26 in the vehicle coincides with the dimension between the upper surface and the lower surface of the Rokka Inner 16, and the lower surface portion 34 is joined to the lower surface of the Rokka Inner 16.

A strut bar bracket 44 for supporting a strut bar (not shown) is attached to a portion of the lower surface 40 of the rear floor side member 26 that protrudes upward from the vehicle and near a bending start point of the vertical wall portion 30. ing. The strut bar bracket 44 is formed in a substantially U-shape with leg portions 46 and 48 parallel to each other, with the front side of the vehicle as a bottom surface. A flange 50 is formed at the upper end of the leg plate 46 on the outer side of the vehicle and is bent toward the leg plate 48 on the inner side of the vehicle, and is joined to the lower surface 40 of the rear floor side member 26. A tongue piece 52 bent at a substantially right angle toward the outside of the vehicle is formed at the lower end of the leg plate 46 on the outside of the vehicle, and is disposed along the lower surface 40 of the rear lower side member 26.
A flange 54 is formed at the tip of the tongue piece 52 and is joined to the lower surface 40 of the rear floor side member 26.

On the other hand, a flange 56 is formed at the upper end of the leg plate 48 inside the vehicle. The flange 56 is bent in accordance with the shape of the vehicle inner vertical wall 32 of the rear flosser side member 26, and is joined to the vehicle inner vertical wall 32.

In the strut bar bracket 44, circular holes 58 for attaching a strut bar are formed on surfaces of the leg plates 46 and 48 corresponding to each other, and a load applied to the tire wheel is input from the circular holes 58.

 The operation of the present embodiment will be described below.

When a load is applied from the rear of the vehicle, the load is first input to the rear floor side member 26. The input load is transmitted to the front of the vehicle along the rear floor side member 26, and transmitted to the Rokka Inner 16 by the curved vertical wall portion 30. Here, on the vehicle front side of the rear floor side member 26, the lower surface portion 40 is enlarged in the vehicle downward direction, and the joining height dimension to the Rokka Inner 16 matches the height dimension of the Rokka Inner 16. Therefore, there is no difference between the rigidity of the rocker panel 12 and the rigidity of the rear floor side member 26. Accordingly, the load does not concentrate on the curved portion of the rear floor side member 26, and the load is smoothly transmitted to the rocker panel 12.

By the way, the rear floor side member 26 does not have all the height dimensions coinciding with the rocker panel 12, but the lower surface portion 40 is convex upward in the vehicle rearward of the vehicle from the bending start point. The strut bar bracket 44 is joined. For this reason, by attaching the strap bar bracket 44, the minimum ground clearance can be maintained without lowering the vehicle ground clearance.

In the present embodiment, only the height of the rear floor side member 26 on the vehicle front side is enlarged downward of the vehicle so as to match the height of the rocker panel 12, so that the rigidity difference between the rear floor side member 26 and the rocker panel 12 is increased. And transmission of the load can be made smoother. For this reason,
There is no inconvenience that the load concentrates on the bending start point of the rear floor side member 26, and the rear floor side member 26
Can be prevented from being deformed. Further, since the mounting position of the strut bar bracket 44 is secured as before, it does not fall below the minimum ground clearance.

Further, the rigidity of the rear floor cross member 26 itself can be increased only by changing the shape of the rear floor side member 26 without adding a reinforcing member or the like, so that the number of assembly steps and the vehicle weight are increased due to an increase in the number of parts. There is no problem that causes

〔The invention's effect〕

As described above, the rear underbody structure of the vehicle according to the present invention is capable of efficiently and smoothly transmitting the load from the rear of the vehicle input to the rear floor side member to the rocker panel without increasing the number of assembly steps and the vehicle weight. It has an excellent effect that it can be produced.

[Brief description of the drawings]

1 is a perspective view showing a rear underbody structure according to the present embodiment, FIG. 2 is an exploded perspective view of FIG. 1, and FIG. 3 is FIG.
FIG. 4 is a sectional view showing a conventional rear underbody structure taken along the line I-III. 10 ... Rear underbody part, 12 ... Rokka panel, 26 ... Rear floor side member, 30 ... Vertical wall part, 40 ... Bottom part, 42 ... Step part, 44 ... Strut bar bracket.

Claims (1)

(57) [Claims] A rocker panel disposed at both ends in the width direction of a vehicle, and a vehicle front end of a vehicle inner vertical wall portion which is disposed offset from the rocker panel inside the vehicle, is curved outwardly of the vehicle. And a rear floor side member joined to the rocker panel, the height of which is enlarged corresponding to the height of the rocker panel, and a lower surface on the vehicle rear side of the step of the rear floor side member. A rear underbody structure for a vehicle having a strut bar bracket joined to a portion.