JP2004345611A - Car body frame structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a car body frame structure capable of saving weight of a side member supporting a floor panel and securing stiffness and strength of the side member by making good use of the closed cross section of a closed cross section member with a simple structure. <P>SOLUTION: In the car body frame structure, the side member 9 supporting the floor panel 1 from below is configured by performing bending work to an extruded member with its closed cross section continued in the longitudinal direction as much as bending work is permitted. In the portion of the side member 9 not running along the shape of the floor panel 1, a structure with braces 12a-12c supporting the portion from below according to the shape of the floor panel part is adopted. Thus, the floor panel 1 is supported from the front to the rear part by the side member 9 formed of one extruded member with a continuing hollow part. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a vehicle body frame structure that employs a closed-section member for a side member extending in the vehicle front-rear direction.
[0002]
[Prior art]
In automobiles (vehicles), it is required to increase the rigidity of the vehicle body while reducing the weight.
[0003]
Accordingly, a side member (a member extending in the front-rear direction of the vehicle body) that supports the floor panel of the vehicle from below is provided with a member in which the front end to the rear end of the vehicle body are integrated, for example, a hollow section made of a light alloy such as an aluminum alloy ( It has been considered that an elongated extrusion member having a (closed cross-sectional shape) is employed to reduce both the weight and rigidity of the vehicle body (for example, see Patent Document 1).
[0004]
By the way, in order to secure a comfortable vehicle interior space, to install a front seat and a rear seat, to secure a luggage space and a power plant space, for example, in the front-rear direction of the floor panel constituting the vehicle body, for example, There are formed portions that become steps or stepped portions, and there are many portions that bend in the vertical direction, such as portions that rise diagonally or in an arc shape on the upper side.
[0005]
When a side member formed by an extruded member is used, it is necessary to perform bending in accordance with the shape of the floor panel in the front-rear direction.
[0006]
Here, in order to ensure higher rigidity by the side members, it is required that the extruded member be continuous in the longitudinal direction with a fixed closed cross section. However, there is a limit to bending this extruded member while maintaining its closed cross-sectional shape. For this reason, the bending of the extruded member has a limit in the size of the arc to be bent, and bending is accepted only within the range in which the bending can be performed.
[0007]
For this reason, in the case of a floor panel which tends to have a complicated shape having a small arc as in recent times, the shape of the side member in the longitudinal direction cannot be matched with the shape of the floor panel.
[0008]
In the case of such a floor panel, instead of bending an extruded member having a closed cross section formed of a light alloy, for example, the floor panel is divided into straight portions in the shape of the floor panel, and the divided side members are separately separated from the floor panel. It has been considered that a side member conforming to the shape of a floor panel is connected by connecting a hollow cast node (joint member) formed in accordance with the shape of the bent portion (see, for example, Patent Document 2). .
[0009]
[Patent Document 1]
JP-A-10-109662
[Patent Document 2]
Japanese Patent Application Laid-Open No. Hei 9-118258
[Problems to be solved by the invention]
However, the side member of the structure that joins the extrusion member at the node at each bent portion has a rigidity of the extrusion member interrupted by a cast node compared to a structure that consists of a single extrusion member from the front to the back. Therefore, the rigidity tends to be low. Moreover, the weight is easy to increase. In addition, the structure tends to be complicated. Therefore, the structure of securing the rigidity by utilizing the specific closed cross section of the extruded member cannot be fully utilized.
[0012]
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a vehicle body frame structure that has a simple structure and effectively utilizes the closed cross section of a closed cross section member to reduce the weight of a side member supporting a floor panel and to further secure the rigidity of the side member. Is to provide.
[0013]
[Means for Solving the Problems]
According to the first aspect of the present invention, in order to achieve the above object, the side member supporting the floor panel from below has a closed cross-section that conforms to the shape of the floor panel within a range in which a member that continues in the longitudinal direction can be bent. Using a structure formed by performing bending processing, a portion of the side member that does not conform to the shape of the floor panel is provided with a support member that supports the portion that does not conform to the shape of the floor panel from below. Adopted structure.
[0014]
With this configuration, the floor panel from the front portion to the rear portion of the vehicle body is supported by the side members formed of one-piece members having a continuous closed cross section.
[0015]
In the invention according to claim 2, in addition to the above object, the support member is formed integrally with a cross member extending in a direction intersecting with the side member so that the support portion also functions as a frame part of the vehicle body.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described based on the first embodiment shown in FIGS.
[0017]
1 to 4 show part of a body frame structure of an automobile (vehicle) to which the present invention is applied, specifically, an underbody structure. This is a chassis frame that supports from below.
[0018]
The floor panel 1 includes, for example, a dashboard portion 3 that rises, for example, above the vehicle body, and a flat panel portion 4 that forms a front side of a floor surface in a vehicle compartment (for example, a portion where a front seat is installed). Similarly, a panel portion 5 that rises in a stepwise manner and forms a rear side (for example, a portion where a rear seat is installed) and a flat panel portion 6 that forms a floor surface of a luggage space (not shown) are formed. Among them, the panel portion 5 is a portion having a plurality of small bent portions 7 which are bent in a vertical direction so as to form a step or a stepped portion depending on, for example, a method of installing a rear seat and a request for a luggage space on the rear side. ing. The bent portions 7 of the floor panel 1 that bend in the vertical direction are formed by drawing or, if necessary, bending.
[0019]
The chassis frame 2 has a pair of parallel side members 9 extending in the vehicle longitudinal direction through both sides of the lower surface of the floor panel 1 in the vehicle width direction. These side members 9 have a length from the front end of the vehicle body to the rear end of the vehicle body, for example. Specifically, the side member 9 includes, for example, a member portion 9a protruding forward from the dashboard portion 3 and a member portion 9b integral with the member portion 9a supporting the portion from the dashboard portion 3 to the panel portion 6 from below. It is configured in combination. Various cross members 10a to 10c are connected between the side members 9 to form a ladder.
[0020]
Further, as the side member 9, an elongated extruded member having a closed cross section obtained by extruding a light alloy lump such as an aluminum alloy, for example, an elongated extruded member 11b having a rectangular hollow portion 11a continuous in the longitudinal direction is used. It is. These side members 9 are formed into a shape in the front-rear direction of the floor panel 1 in such a manner that the bending process is performed only within a range in which bending can be performed, for example, a curvature within a range in which a square hollow closed cross-sectional shape can be maintained at a predetermined value. It is bent along. By this bending process, for example, as shown in FIGS. 3 and 4, the foremost side of the member portion 9 b is bent so as to conform to the shape of the base side of the dashboard portion 3. Further, the portion of the rear portion of the member 9b that cannot be bent, that is, the member portion β of the portion corresponding to the region α of the floor panel 1 having the plurality of small bent portions 7 is formed straight without bending. Both end portions of the member portion β are bent so as to follow the shape of a boundary portion between the flat panel portion 4 and the panel portion 6. That is, in the side member 9, a portion excluding a portion corresponding to the region α in which the small bent portion 7 is present is bent into a shape similar to the floor panel 1. The overlapping floor panel 1 and side member 9 are fixed, for example, by welding.
[0021]
On the other hand, a brace 12 as a support member is attached to, for example, an upper surface of a member portion β of the side member 9 which does not conform to the shape of the floor panel 1. As shown in FIGS. 3 and 4, a plurality of, for example, two braces 12 are provided side by side in the front-rear direction of the member portion β. The brace 12a disposed on the front side supports the front side of the region α having the plurality of bent portions 7, and the brace 12b disposed on the rear side supports the rear side of the remaining region α. More specifically, each of the braces 12a and 12b is formed, for example, by variously processing an extruded material to form a mounting surface (not shown) on the lower surface that conforms to the upper surface shape of the member portion β, and has a stepped area α on the upper surface. It is composed of a trapezoidal block having a support surface 13 that follows the shape of the panel portion that is raised to the upper side, and if it is installed on the upper surface of the member portion β, the area α of the floor panel 1 is supported from below. It is. That is, as shown in FIGS. 3 and 4, for example, the braces 12a and 12b are assembled on the member portion β of the bent side member 9, and then the floor panel 1 is mounted on the upper surface of the side member 9. The floor panel 1 is supported from below by the support surfaces 13 of the braces 12a and 12b. The floor panel 1 and the support surface 13 are fixed to each other by, for example, welding.
[0022]
The side member 9 is formed from an extruded member 11b that conforms to the shape of the majority of the floor panel 1, and a portion that cannot be processed by bending, that is, a region α having a small bending radius, is used to support the region α. By adopting a structure corresponding to the braces 12a and 12b having an appropriate shape, the floor panel 1 can be supported from the front of the vehicle body to the rear of the vehicle body by a single extrusion member 11b having a continuous hollow portion 11a (closed cross section). Thus, the rigidity of the side member 9 can be improved. In addition, since the braces 12a and 12b are used only to support a portion not conforming to the shape of the floor panel 1, the number of braces used is reduced. Therefore, the frame structure provided by the side members 9 is structurally simple and excellent in weight reduction.
[0023]
That is, with a simple structure, both the weight reduction and the rigidity of the side member 9 can be achieved by effectively utilizing the specific closed cross section of the pushing member 11b. In particular, as shown in FIG. 4, when the side member 9a projecting outward from the floor panel 1 is also integrally formed with the pushing member 11b supporting the floor panel 1, the rigidity in the front-rear direction of the vehicle body is remarkably increased.
[0024]
FIG. 5 shows a second embodiment of the present invention.
[0025]
This embodiment shows a modification of the first embodiment, which has a structure in which the area α of the floor panel 1 is supported by, for example, three braces 12a to 12c, and furthermore, a part of the braces is arranged, for example, in the middle. A member spanned between the side members 9, 9, that is, a cross member 10e extending in a direction intersecting with the side member 9, is integrally connected between the support surfaces 13 of the brace 12c. In the drawing, reference numeral 10g denotes a cross member which is disposed near and attached to the cross member 10e.
[0026]
When such a structure is adopted, the brace 12c also functions as a component of the chassis frame 2, so that there is an advantage that the rigidity and strength can be further improved.
[0027]
FIG. 6 shows a third embodiment of the present invention.
[0028]
This embodiment shows a modification of the first and second embodiments, in which the support surface 13 of the brace 12b installed on the rear side of each member portion β is formed by a mountain-shaped slope, and the brace 12b The cross member 10f is attached between the support surfaces 13 to improve the rigidity by combining the cross member 10f and the brace 12b. That is, the embodiment has a structure in which the brace 12b and the cross member 10f are combined separately.
[0029]
Even in this case, the same effect as in the second embodiment can be obtained.
[0030]
However, in the second and third embodiments, the same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.
[0031]
The present invention is not limited to the above-described embodiments, and may be implemented with various modifications without departing from the gist of the present invention. For example, in each of the above-described embodiments, the structure in which the brace is installed on the upper surface of the side member has been described. However, the structure is not limited to this, and the brace may be installed in the side portion of the side member. Further, in each embodiment, the side members continuous from the front end to the rear end of the vehicle body are described, but the side members may have a structure continuous from the front part to the rear part of the floor panel. In each embodiment, the floor panel 1 has an integral structure. However, for example, a dash panel corresponding to the dashboard section 3, a front floor panel corresponding to the panel section 4, panel sections 5, 6, and a bent section are provided. The floor panel may be a three-part floor panel with the rear floor panel corresponding to 7.
[0032]
【The invention's effect】
As described above, according to the first aspect of the present invention, the closed section of the closed section member is effectively utilized, and the floor panel is supported by a single closed section member from the front of the vehicle body to the rear of the vehicle body. Therefore, with a simple structure, the weight and rigidity of the side member supporting the floor panel can be reduced.
[0033]
According to the second aspect of the present invention, in addition to the above-described effects, the support member also functions as a frame part of the vehicle body, so that an effect of exhibiting higher rigidity can be achieved.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view showing a vehicle body frame structure according to a first embodiment of the present invention.
FIG. 2 is a perspective view showing a chassis frame in which side members and support members of the vehicle body frame structure are disassembled.
FIG. 3 is a side sectional view for explaining a case where a floor panel is combined with a side member.
FIG. 4 is a side sectional view showing a state where the floor panel is combined with a side member.
FIG. 5 is a perspective view showing a main part of a second embodiment of the present invention.
FIG. 6 is an exploded perspective view showing a main part of a third embodiment of the present invention.
[Explanation of symbols]
1 ... Floor panel, 9 ... Side member, 10e ... Cross member, 12b, 12c ... Brace (support member).

Claims (2)

A floor panel configured with a plurality of bent portions that bend in the vertical direction of the vehicle body,
A shape of the floor panel within a range in which a closed cross section can be bent into a member continuing in the longitudinal direction, which is disposed at least below the floor panel from the front of the vehicle body to the rear of the vehicle body so as to support the floor panel from below. A side member configured by bending along the
A vehicle body frame structure comprising: a support member provided on a portion of the side member that does not conform to the shape of the floor panel, and supporting the portion that does not conform to the shape of the floor panel portion from below. . The vehicle body frame structure according to claim 1, wherein the support member is integrated with a cross member extending in a direction intersecting with the side member.

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