Structure for front part of automotive vehicle body

Abstract: A structure for a front part of an automotive vehicle body, having front side frames 2 extending longitudinally above a front axle 1, intermediate frames 5 connecting the rear ends of the side frames 2 to the front ends of floor frames 4 extending longitudinally underneath a floor of a passenger compartment and a dash panel 7 separating an engine compartment 6 from the passenger compartment, wherein the dash panel extends upwardly from longitudinally intermediate portions of said intermediate frames. With this construction, since the connecting points between the front side frames and the intermediate frames, i.e., the part that is to be bent by virtue of a crashload, are located forward of he dash panel, the effect on the deformation of the passenger compartment by the deformation of the frames can be alleviated.

Description: The present invention relates to a structure for a front part of an automotive vehicle body. A front part of an automotive vehicle body comprises front side frames extending longitudinally above a front axle, intermediate frames connecting the rear ends of the front side frames to the front ends of floor frames extending longitudinally underneath a floor of a passenger compartment and a dash panel separating an engine compartment from the passenger compartment. Conventionally, it is common that the dash panel rises from connecting portions between the front side frames and the intermediate frames (refer to Japanese Patent Unexamined Publication No. Hei.10-138953). However, a bending moment applied to the frames of a vehicle when a crash load is imparted from the front becomes a maximum at the respective connecting portions between the intermediate frames and the front side frames and at the respective connecting portions between the intermediate frames and the floor frames. Therefore, when the vehicle undergoes a frontal collision, the connecting portions between the rear ends of the front side frames and the front ends of the intermediate frames are bent, and in particular, with a structure being adopted in which the rear ends of the front side frames abut against a vertical plane of the dash panel, it is inevitable that the deformation so made affects as far as the passenger compartment. Since the excessive deformation of the passenger compartment is not preferable from an occupant protection point of view, conventionally, the frames are reinforced such that it is difficult to deform the connecting portions between the frames and the dash panel. However, there is caused a problem that the aforesaid reinforcement increases the vehicle weight. The present invention was made with a view to solving the problem which is inherently found with the conventional technique. It is one object of the invention to provide a structure for a front part of an automotive vehicle body which can provide a reduction in the vehicle weight whilst maintaining or improving the level of protection of the passenger compartment. According to the invention, there is provided a structure for a front part of an automotive vehicle body comprising: a front side frame extending in a longitudinal direction above a front axle; an intermediate frame connecting the rear end of said front side frame to the front end of a floor frame, said floor frame extending in a longitudinal direction underneath a floor of a passenger compartment, and said intermediate frame being forwardly and upwardly inclined; and a dash panel separating an engine compartment from said passenger compartment, wherein said dash panel extends upwardly; characterised in that said dash panel extends upwardly from a longitudinally intermediate portion of the inclined intermediate frame such that the rear ends of the front side frame do not abut against the vertical plane of the dash panel. With this construction, since the connecting points between the front side frames and the intermediate frames, that is, the portions which are bent by virtue of a crash load, are located forward of the dash panel, the effect on the passenger compartment by the deformed frames is alleviated. A preferred embodiment of the invention will now be described by way of example and with reference to the accompanying drawings, in which: Fig. 1 shows a schematic view of a structure for an automotive vehicle body according to the invention; and Figs. 2A-2C show an explanatory comparative view for comparing the structure according to the invention with a conventional one. Fig. 1 shows schematically a structure for a front part of an automotive vehicle to which the invention is applied. The illustrated structure for the front part of the automotive vehicle body comprises front side frames 2 extending longitudinally above a front axle 1, inclined forwardly upwardly intermediate frames 5 connecting rear ends of the front side frames 2 to front ends of floor frames 4 extending longitudinally underneath a floor of a passenger compartment 3, and a dash panel 7 separating the passenger compartment 3 from an engine compartment 6. The dash panel 7 extends upwardly from intermediate portions of frame 5 which are located between the respective connecting portions of the front side frames 2 and floor frames 4. A lower edge of the dash panel 7 is connected to a floor panel 8 provided so as to extend from rear upper surfaces of the intermediate frames 5 to upper surfaces of the floor frames 4. Then, according to a conventional structure (Fig. 2A) on which the pre-characterising part of claim 1 is based, in which rear ends of front side frames 21 abut against a vertical plane of a dash panel 71, connecting points A1 between the front side frames 21 and intermediate frames 51 are located at positions in the vicinity of the dash panel 71. In this construction, when a bending moment is applied to the front side frames 2 and the intermediate frames 5 by virtue of a load generated in the longitudinal direction of the vehicle body when the vehicle comes into a frontal collision, a bending moment diagram around a Y axis becomes as shown by a broken line in Fig. 2C, whereby large peaks are generated at the respective connecting points A1, B1 between the intermediate frames 51 and the front side frames 21 and the floor frames 41. Due to this, when the connecting points A1, B1 between the front side frames 21 and the intermediate frames 51 are bent by virtue of a crash load, a deformation so generated results in a large rearward displacement of the dash panel 71, in other words, the deformation of the passenger compartment 31. According to the preferred embodiment of the invention, however, since the connecting points A2 between the front side frames 2 and the intermediate frames 5 are located forward of the vertical plane of the dash panel 7 (Fig. 2B), the rearward displacement of the dash panel 7 by virtue of bends generated at the connecting points A2 between the front side frames 2 and the intermediate frames 5 is reduced. Further, since the inclined angle  of the intermediate frames 5 relative to the horizontal plane can be reduced by locating the connecting points A2 between the front side frames 2 and the intermediate frames 5 forward further than the conventional structure, as shown by a solid line in Fig. 2C, the peak of the bending moment can also be reduced. This, of course, contributes largely to reducing further the deformation amount of the passenger compartment 3. Thus, there is a reduction in the deformation of the passenger compartment due to the deformation of the part extending from the front side frames to the floor frames by not making the rear ends of the front side frames abut against the vertical plane of the dash panel, and there are smooth and easy angle transitions at the curved portions where the front side frames and floor frames reach the intermediate frames, respectively. Therefore, the construction described can largely contribute to the realization of the compatibility of a reduction in vehicle weight and the protection of the passenger compartment at an enhanced level. While the above description relates to a preferred embodiment of the invention, it will be clear to those skilled in the art that various changes and modifications may be made therein without departing from the scope of the the appended claims.

Claims: A structure for a front part of an automotive vehicle body comprising: a front side frame (2) extending in a longitudinal direction above a front axle (1); an intermediate frame (5) connecting the rear end of said front side frame (2) to the front end of a floor frame (4), said floor frame extending in a longitudinal direction underneath a floor of a passenger compartment (3), and said intermediate frame (5) being forwardly and upwardly inclined; and a dash panel (7) separating an engine compartment (6) from said passenger compartment, wherein said dash panel (7) extends upwardly; characterised in that said dash panel (7) extends upwardly from a longitudinally intermediate portion of the inclined intermediate frame (5) such that the rear ends of the front side frame (2) do not abut against the vertical plane of the dash panel (7). A structure as claimed in claim 1, wherein the lower edge of the dash panel (7) is connected to a floor panel (8) which extends from the rear upper surface of the intermediate frame (5) to the upper surface of the floor frame (4). A structure as claimed in claim 1 or 2, wherein said intermediate portion is located between a connecting portion defined between the front side frame (2) and the intermediate frame (5) and a connecting portion defined between said intermediate frame (5) and said floor frame (4).

Inventors: ISHIBASHI KENGO, OHMURA SHIGERU, ISHIBASHI, KENGO, OHMURA, SHIGERU
Applicants: HONDA MOTOR CO LTD, HONDA GIKEN KOGYO KABUSHIKI KAISHA
Application year: 2000
Main classification: B62D25
IPC codes: B62D25, B62D21