JPH01103585A - Rear car-body construction for automobile - Google Patents

Abstract

PURPOSE:To secure a living space for occupants with no increase in weight and cost at the time of a rear-end collision by forming a cavity deforming and bending the rear part of a floor-frame downward when an impact load above a specified value is inputted from the rear part. CONSTITUTION:An impact load inputted from the rear-end part of an extension frame at the time of a rear-end collision acts on the rear-end part of a floor- frame rear part 1b as a buckling load. Accordingly, a cavity 1c caved-in downward is formed in the upper end part adjacent to the rear-end part of the floor- frame rear part 1b, and V-shaped beads 1d extend downward from the cavity 1c are formed on both sides of the floor-frame rear part, reinforcements arranged in the closed cross-section of the floor-frame rear part 1b being formed relatively lower in the part where the beads 1d are formed. Thus, since the stresses cuased by a buckling load on the rear-end part concentrate on the part where the cavity 1c and the beads 1d are formed, the floor-frame rear part 1b is positively deformed and bent downward.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a rear body structure of an automobile, particularly an automobile equipped with a floor frame extending in the longitudinal direction of the vehicle body and having a rear portion offset upward. This relates to the rear body structure.

(Prior Art) Generally speaking, an automobile is provided with a floor frame extending in the longitudinal direction of the vehicle body on both sides of the floor panel.
A crank-shaped kick-up part is formed in the middle of the floor frame, and the part behind the kick-up part is often offset upward. In automobiles with such a rear body structure, a passenger seat is sometimes placed on a floor panel located at the rear of the floor frame that is offset upward. If an impact load of more than a predetermined value is input to the rear end of the floor frame during a collision (in which the impact load is applied from the rear of the vehicle), the kick-up part acts as a kind of joint, and the rear end of the kick-up part acts as a joint. A buckling load will act on the rear part of the floor frame. In this case, since the rear part of the floor frame is formed to be offset upward, the rear part of the floor frame is likely to bend upwardly due to the buckling load. In addition, the load input point for the floor frame is, for example,
As disclosed in Japanese Patent No. 124441, it is generally located on the center axis of the floor frame, but in FR pan-type vehicles, etc., the suspension layout space becomes larger in the vertical direction, and the rear part of the floor frame is In vehicles where the amount of upward offset is large and the bumper position needs to be lowered due to the styling requirements of the vehicle, the center axis at the rear of the floor frame should be moved against the pump bracket, which is the load input point. This may result in an upward offset. Therefore, in a vehicle having such a rear body structure, it is necessary to prevent the rear part of the floor frame from bending upward when rearward, making it difficult to secure sufficient living space for the occupants. .

For this reason, conventional measures have been taken to improve the bending rigidity of the rear part of the floor frame, such as increasing the thickness of the floor frame or providing reinforcement at the rear part of the floor frame.

(Problems to be Solved by the Invention) [7] However, taking such measures is not preferable because it leads to an increase in vehicle weight and cost.

The present invention has been made in view of the above circumstances, and provides a rear body structure for an automobile that can secure a living space for occupants at the rear without increasing the vehicle weight or cost. The purpose is to provide the following.

(Means for Solving the Problems) The rear body structure of an automobile according to the present invention bends and deforms the rear part of the floor frame downward when rearward by forming a recess that retracts downward at a predetermined position in the rear part of the floor frame. The present invention is constructed in such a manner that the above object can be achieved.

In other words, the rear body structure of an automobile includes a floor frame that extends in the longitudinal direction of the vehicle body and is formed with the rear part offset upward, and an impact load of a predetermined value or more is input to the floor frame from the rear. The present invention is characterized in that a recessed portion recessed downward is formed at a predetermined position in the rear portion of the floor frame so as to bend and deform the rear portion of the floor frame downward.

The above-mentioned "predetermined position" and "four parts" refer to a specific position or It is not limited to a specific shape.

In addition, in this case, it is not necessarily necessary to bend the entire rear part of the floor frame downward, and even if a part of the rear part of the floor frame is bent downward, at this time, the rear part of the floor frame Other parts are displaced upward by a predetermined amount or more (that is, to the extent that it is no longer possible to secure a sufficient living space for a passenger seated on a seat placed on a floor panel located at the rear of the floor frame). Anything that can prevent this is fine.

(Function) As shown in the above configuration, a recess that retracts downward is formed at a predetermined position at the rear of the floor frame, so that when an impact load of more than a predetermined value is input to the floor frame from the rear, the floor frame The rear part of the frame is bent downward.

(Effects of the Invention) Therefore, according to the present invention, there is no risk that the seat placed on the floor panel located at the rear of the floor frame will be displaced upward by a predetermined amount or more even when the seat is in the rear, thereby saving the occupant's living space. Furthermore, such effects can be obtained with a simple configuration without increasing the weight or cost of the vehicle body.

(Examples) Examples of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a schematic diagram showing an embodiment of the rear body structure of an automobile according to the present invention.

A pair of floor frames 1 with a roughly U-shaped cross section are installed on both sides of the vehicle.
extend in the longitudinal direction of the vehicle body, and a floor panel 2 is disposed on the upper surface of these floor frames 1 so as to form a closed cross section with the floor frame 1. A crank-shaped kick-up portion 1a is formed in a portion of the floor frame 1 near the front end of the rear wheel 3, and a portion rearward of the kick-up portion la (hereinafter referred to as the rear portion of the floor frame 1b) is formed upward. offset. A seat 4 located in the third row from the front in the vehicle interior is placed in a portion of the floor panel 2 located at the front end of the floor frame rear portion 1b. On the other hand, the rear end portion of the rear floor frame 1b is joined to a cross member 5 extending in the vehicle width direction, and an extension frame 6 having a substantially trapezoidal cross section that projects rearward is joined to the rear surface of this cross member 5. .

This extension frame 6 is provided approximately coaxially with the floor frame rear part 1b, and its tip end is connected to the extension frame 6.
A bumper 8 is located below and is connected to the floor frame rear part 1b and the cross member 5 via a bracket 7.
It protrudes further rearward than the bumper stay 9 for supporting the bumper stay 9. Therefore, at the rear, an impact load is input to the extension frame 6 via the bumper 8, as shown by arrow A in the figure.

A four part 1c recessed downward is formed at the upper end of a portion near the rear end of the rear part 1b of the floor frame, and a four part 2a recessed downward is formed in the floor panel 2 along the shape of the recessed part 1c. ing. In this way, by forming the recess 1c in the rear part of the floor frame 1b, the rear part of the floor frame 1b is actively bent downward at the recess 1c in response to an impact load input at the rear of the vehicle. This is to prevent upward bending deformation. Therefore, although the front end of the rear floor frame 1b is slightly displaced upward due to the impact load, the amount of displacement is small, and the living space of the occupant 10 seated on the seat 4 is not unduly narrowed due to this displacement. do not have.

In order to more reliably perform the downward bending deformation of the rear part 1b of the floor frame, the four parts 1c of the rear part 1b of the floor frame are
There is a ■-shaped bead 1d on both sides of the part where is formed.
are formed respectively.

FIG. 2 is an enlarged detailed view of the section ``■'' in FIG. 1, showing the vehicle body structure in the vicinity of the rear end of the rear floor frame 1b. In addition, FIG. 3 is a view taken along the line ■-■ in FIG.
FIG. 2 is a plan view with the floor panel 2 removed.

As shown in FIG. 2, the bottom part of the floor frame rear part 1b located below the recess 1c is also formed to be recessed downward substantially parallel to the recess 1c, and the closed cross section of the floor frame rear part 1b A frame reinforcement 11 for reinforcing the floor frame rear part 1b is disposed inside. The frame reinforcement 11 has a U-shaped cross section, is disposed along the bottom surface and both side surfaces of the floor frame rear portion 1b, and is joined to both side surfaces of the floor frame rear portion 1b by spot welding. Both side portions of the reinforcement 11 are formed such that the height of a portion Lla located below the bead ld formed on both side portions of the rear portion lb of the floor frame is relatively low. As shown above, the rear part of the floor frame [
The bottom part located below the four part IC of b is formed by recessing downward, and the frame reinforcement 1
By forming the low-height portions 11a on both side surfaces of the floor frame 1, the downward bending deformation of the rear end portion 1b of the floor frame at the rear portion can be more reliably performed.

The cross member 5 to which the rear end portion of the floor frame rear part 1b is joined is formed in a closed section shape by the outer panel 1z, the inner panel 13, and the floor panel 2, and the cross member 5 is formed in a closed section shape by the outer panel 1z, the inner panel 13, and the floor panel 2, and the cross member 5 is formed in a closed cross section shape by the outer panel 1z, the inner panel 13, and the floor panel 2. The portion includes a first reinforcement 14 that is joined to the inner panel 13 and has a substantially U-shaped vertical cross section in the vehicle width direction, and a second reinforcement 15 that is joined to the second reinforcement 14 and the outer panel I2. , a first reinforcement 14, a second reinforcement 15, an inner panel 13, and a third reinforcement 16 joined to the floor panel 2. These first and second
and Third Reinforcement 14.15. 16, further box-shaped joints are formed within the closed cross section of the cross member 5.

The extension frame 6 provided directly behind this box-shaped joint is connected to a lower member 17 that is joined to the outer panel 12 of the cross member 5 and has a substantially U-shaped vertical section in the vehicle width direction, and is arranged on the upper surface of this lower member 17. an upper member 18 joined to the upper end and rear end of the lower member 17; the lower member 17, the upper member 18 and the outer panel 1;
It is formed into a truncated pyramid-shaped closed cross section that tapers toward the rear, and the center position of the rear end in the vertical and horizontal directions is located at the closed cross section of the rear part of the floor frame lb. It almost coincides with the central axis.

Rear end of floor frame rear part 1b and cross member 5
A bracket 7 that connects the bumper stay 9 to the bumper stay 9 is joined to both side surfaces of the rear part 1b of the floor frame, the inner panel 13 of the cross member 5, and the front end of the bumper stay 9. Furthermore, a connecting bracket 20 is connected to the front end of the bracket 7 to connect the bracket 7 to the bottom of the rear part 1b of the floor frame, and an anchor plate 21 is provided on the side surface of the bracket 7. has been done.

At the rear end of the frame reinforcement 11 disposed within the closed section of the floor frame rear part 1b, a protrusion 1e that protrudes rearward than the floor frame rear part 1b is formed. It is joined to the inner panel 13 of the member 5.

Next, the operation of this embodiment will be explained.

The state of deformation of the rear part of the floor frame tb when the vehicle is running is as shown by the broken line in Fig. 1.As shown in Fig. 2, the rear body structure of the automobile according to this embodiment A joint is formed in the closed cross section of the cross member 5 at Since the center point of point ) is configured to be approximately coaxial with the central axis of the floor frame 1b, the impact load input from the rear end of the extension frame 6 at the time of writing will be applied to the rear end of the floor frame rear part 1b. In the vicinity of the rear end of the floor frame rear part 1b, a recess 1c that retracts downward is formed in the upper end of the floor frame rear 1b, and the lower end is also roughly called the recess 1c. A V-shaped bead ld extending downward from the concave portion 1c is formed on both side surfaces of the rear part 1b of the floor frame to maintain continuity of the ridge lines at the upper ends of both side surfaces in the front-rear direction. The frame reinforcement 11, which is arranged in a closed section of the rear part 1b of the floor frame, is located below the bead 1d.
Since the rear part 11a of the floor frame is formed relatively low, when a buckling load is applied to the rear end of the floor frame rear part 1b, stress is concentrated on the part where the bead 1d of the concave IC is formed, so that the rear part 1b of the floor frame reliably This results in a downward bending deformation.

FIG. 4 is a side sectional view showing another embodiment of the rear body structure of an automobile according to the present invention.

In this embodiment, instead of providing the first to third reinforcements 14, 15, and 18 in the cross member 5 to form knots, the outer panel 12 of the cross member 5
An opening 12a (see FIG. 5) is formed in the extension frame 6, and the front ends of the lower member 17 and upper member 18 of the extension frame 6 are extended forward and joined to the inner panel 13 of the cross member 5. With this configuration, the rear body structure can be simplified, and the impact load input to the rear end of the extension frame 6 can be reliably transmitted to the rear end of the floor frame rear part 1b. can.

[Brief explanation of the drawing]

Fig. 1 is a schematic side view of a vehicle body showing an embodiment of the rear body structure of an automobile according to the present invention, Fig. 2 is an enlarged detailed view of the part ■ in Fig. 1, and Fig. 3 is an arrow marked by the -■ line in Fig. 2. 4 and 5 are views similar to FIG. 2 and perspective views showing other embodiments. 1...Floor frame tb...Floor frame rear part 1c...4 Part 5

Claims (1)

[Scope of Claims] A rear body structure of an automobile including a floor frame that extends in the front-rear direction of the vehicle body and is formed with a rear part offset upward, wherein the floor frame is subjected to an impact load of a predetermined value or more from the rear. A rear body structure for an automobile, characterized in that a concave portion recessed downward is formed at a predetermined position in the rear part of the floor frame so as to bend and deform the rear part of the floor frame downward when the rear part of the floor frame is input. .