Body structure for vehicle

Abstract: To simplify both positioning and temporary fixing in assembling a dash panel (1) to a reinforcement member (4) engagement parts (21) are arranged on both lateral end portions of the reinforcement member (4) for engagement between the member (4) and the panel (1). In the process of assembling, the panel (1) is pinched between the engagement parts (21) at both ends of the panel (1).

Description: The present invention relates to a body structure for vehicle. Particularly, it relates to the (vehicle) body structure around a dash panel which separates a vehicle cabin and a front compartment or a rear compartment of the vehicle. Generally, when assembling a plurality of body panel members provided by press working to construct a vehicle body, the positioning of the respective body panel members is carried out by attaching them to body jigs prescribing the relative positions of the members. Further, the welding operation of the panel members to be welded is performed on condition that the members are pinched by respective clamping jigs for temporarily holding (see Japanese Unexamined Patent Publications Nos. 10-264862 and 7-309254). In recent years, it has been adopted to construct the vehicle body by plural panel members consisting of extrusions or castings of lightweight metal, such as aluminum alloy, in place of the press moldings, in view of making the lightweight vehicle body compatible with its rigidity. For example, there is developed a vehicle body structure where a dash panel separating the vehicle cabin and the front compartment (or the rear compartment) consists of an extrusion having an improved rigidity. In the structure, the extrusion is provided with a closed sectional structure having inner and outer walls and obtained by extruding the above lightweight metal to the vehicle's width direction. The so-constructed dash panel is reinforced by a reinforcement member which is made of a casting of lightweight metal and connected to the under face of the dash panel. However, the above-mentioned positioning jigs and the clamping jigs have been still required to connect the dash panel with the reinforcement member in spite of such the measures for the lightweight vehicle body compatible with its rigidity. It means that the above-mentioned assembling form causes enormous number of positioning and clamping jigs to be required every sort of vehicles and every process. Consequently, with the addition of installation cost and steps of setting the jigs, the labor cost is apt to increase disadvantageously. DE 297 22 344 U discloses a vehicle body structure in accordance with the preamble of claim 1. Under such a circumstance, it is an object of the present invention to provide a vehicle body structure by which it is possible to properly position the dash panel constructed by extrusion of lightweight metal and the reinforcement member constructed by casting of lightweight metal and also possible to temporarily and properly hold the dash panel and the reinforcement member without using any positioning or clamping jig. The present invention provides a vehicle body structure as set forth in claim 1. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a perspective view of the overall outward appearance of a vehicle body to which the present invention is to be applied; Fig. 2 is an exploded perspective view showing a dash panel and a reinforcement member in accordance with one embodiment of the invention; Fig. 3 is a perspective view of the dash panel and the reinforcement member of Fig. 2, showing their assembled condition; Fig. 4 is a sectional view of the dash panel and the reinforcement member in the assembled condition, taken along a line A-A of Fig. 2; Fig. 5 is a sectional view showing one process for the assembling condition of Fig. 4; and Fig. 6 is a sectional view of the dash panel and the reinforcement member, taken along a line B-B of Fig. 2. DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below, with reference to the drawings. Figure 1 illustrates a vehicle body VB which includes a dash panel (also known as dash cross member) 1 and a reinforcement member 4 constituting the vehicle body structure of the invention. In the shown state, the dash panel 2 is connected with the front end of a floor panel 3. On both sides of the dash panel 1 in a direction along the width of the vehicle body VB, there are provided a pair of front side members 6 which project in front. The leading ends of the front side members 6 are together connected with a first cross member 32 extending along the direction along the width of the vehicle body VB. Note that this direction will be referred as "vehicle width direction" or "width-direction", hereinafter. Figs. 2 and 3 show the dash panel 1 which defines a front compartment FC for accepting a not-shown automotive power unit (e.g. engine) in front of a vehicle cabin R. The dash panel 1 includes an inclined toe board 1A and a vertical wall part 1B rising generally perpendicularly from the board 1A. The dash panel 1 has a tunnel fitting part (notch) 2 arranged at the center of the toe board 1A in the vehicle width direction, for fitting with a tunnel part 3A of the floor panel 3. On condition that the tunnel part 3A of the floor panel 3 is fitted into the notch 2 and the front end of the floor panel 3 overlaps with the rear part of the toe board 1A, the dash panel 1 is fixed to the floor panel 3 by welding. The reinforcement member 4 is joined to the underside of the dash panel 1, extending from the toe board 1A to the vertical wall part 1B. The reinforcement member 4 is provided, on left and right sides thereof, with a pair of arm parts 5 which extend forward. As shown in Fig. 3, respective rear ends of the above front side members 6 and a pair of braces 6A are together welded to the arm parts 5 of the reinforcement member 4. According to the embodiment, the dash panel 1 can be provided by an extrusion of lightweight metallic material, such as aluminum alloy, in the vehicle width direction. By the extrusion, the dash panel 1 is formed with a closed sectional structure having an inner wall 11 and an outer wall 12. Interposed between the inner wall 11 and the outer wall 12 are a plurality of rib walls 13 which also extend to the vehicle width direction, thereby enhancing the rigidity of the panel 1 itself. In the embodiment, the floor panel 3 is also obtained by extruding similar lightweight metallic material in a direction of both in front and in the rear of the vehicle body VB. Similarly, the floor panel 3 is provided with a closed sectional structure having an inner wall 14, an outer wall 15, and a plurality of rib walls 16. Further, a pair of side sills 3B are formed integrally with both sides of the panel 3, respectively. Note the above direction will be referred to "vehicle front/behind direction" or "front/behind-direction" , hereinafter. A casting of the above lightweight metallic material constitutes the reinforcement member 4. The member 4 is provided, on its each side in the vehicle width direction, with a pair of suspension mount bolts7, 8 which project downward. Being partially inserted into the casting, the suspension mount bolt 7 is positioned in the vicinity of the front end of each arm part 5, while the suspension mount bolt 8 is positioned at the main part of the reinforcement member 4. These bolts 7, 8 are connected with a not-shown suspension member for supporting a front suspension. The rear suspension mount bolt 8 has a tapered locating pin 8a formed to project into the vehicle cabin R and a screw part 8b formed on the end of the locating pin 8a. In assembling, the locating pin 8a of the bolt 8 is inserted into a locating hole 12a in the outer wall 12 of the dash panel 1. While, a lid-shaped retainer plate 9 is fitted to an opening 11a in the inner wall 11 of the dash panel 1. The screw part 8b of the bolt 8 is inserted into a through hole 9a in the retainer plate 9 and further tightened by a nut 10 in screw engagement. In this way, the rear end of the suspension member is firmly fastened by the walls 11, 12 of the dash panel 1. The reinforcement member 4 is provided, on its both sides in the vehicle width direction, with engagement parts (clip parts) 21 for pinching both ends of the dash panel 1 in the vehicle width direction (two parts 21 on one side shown in Fig. 2). The engagement parts 21 serve to position the reinforcement member 4 and the dash panel 1 mutually and retain the dash panel 1 on the reinforcement member 4 temporarily. In detail, the reinforcement member 4 has positioning parts 22 arranged on both ends of the member 4 in the vehicle width direction (only one shown in the figure). Each positioning part 22 consists of a shelf portion 23 for mounting the dash panel's end in the vehicle width direction and a flange portion 24 rising from the shelf portion 23. On each side in the vehicle width direction, the above engagement parts 21 are arranged in the flange portion 24 and also between the shelf portion 23 and the flange portion 24. On both sides of the dash panel 1 in the vehicle width direction, substantially L-shaped notches 25 are respectively defined in the dash panel 1 to extend from the upper side of the toe board 1A to the top end of the vertical wall part 1B, corresponding to respective wheel-housing structures (not shown) of the vehicle. Corresponding to the L-shaped notches 25, the positioning parts 22 are also formed to have substantially L-shaped profiles in plan view. On each side of the vehicle in the vehicle width direction, two engagement parts 21 are arranged in respective positions corresponding to an edge 25a in the vehicle width direction and another edge 25b in the vehicle front/behind direction, both edges 25a, 25b defining the L-shaped notch 25. As shown in Figs. 4 and 5, each engagement part 21 has a flat part 26 (the part of shelf 23), a taper face 27 and a slot 28. The flat part 26 is arranged for abutment with the under face of the outer wall 15 of the dash panel 1. The taper face 27 is slanted to the flat part 26 at an open angle  2 (Fig. 4) larger than an open angle  1 (Fig. 6) of an inside generalized face 24a of the flange portion 24, allowing the engagement part 21 in slide contact with respective ends of the inner and outer walls 11, 12. The slot 28 is formed in a position between the flat part 26 and the taper face 27, for engagement with an end 12a of the outer wall 12 of the dash panel 1. As shown in Fig. 5, this slot 28 is provided by using a drill 29 capable of drilling the reinforcement member 4 at a proper angle  3 and a designated length. Note the angle  3 substantially corresponds to one that bisects an angle interposed between the flat part 26 and the taper face 27. Owing to the drilling, the slot 28 is provided with an upper face 28a and an lower face 28b as slanted surfaces. Additionally, the flange portion 24 is provided, in its part profiled by the taper face 27, with a wall thickness that is gradually thickened from the top to the flat part 26. We now describe the assembling method of the above-mentioned dash panel 1 and the reinforcement member 4, including respective steps of mutually positioning, temporary fixing and welding them. In the rough positioning, firstly, the dash panel 1 is perpendicularly superposed piled on the reinforcement member 4 so that both ends (of the vehicle width direction) of the dash panel 1 in slide movement are guided on the inside generalized faces 24a of the flange portions 24 of the positioning parts 22 of the reinforcement member 4. After completing the rough positioning between the dash panel 1 and the reinforcement member 4, let the above-defined "width-direction" ends of the dash panel 1 slide downward along the inside generalized faces 24a and finally fall on the shelf portions 23 (only one shown in Fig. 6). On the dash panel's way to the self portions 23, the flange portions 24 are partially deformed outside due to the slide movement of the width-direction ends of the dash panel 1 on the taper faces 27 of the engagement parts 21. Subsequently, no sooner have both ends of the outer wall 12 of the dash panel 1 climbed over the taper faces 27 succeeding to the slots 28 than the ends of the outer wall 12 fall into the slots 28. Consequently, the outer wall 12 is brought into contact with the shelf portions 23 (i.e. the flat parts 26) through the "width-direction" ends, so that their tips respectively butt against the upper faces 28a of the slots 28 and the tips of the inner wall 12 abut against the taper faces 27, thereby accomplishing both mutual positioning and temporary fixing between the dash panel 1 and the reinforcement member 4 (see Fig. 4). The union between the dash panel 1 and the reinforcement member 4 is basically accomplished by welding a frontal flange 4a between the arm parts 5 of the member 4 to the toe board 1A in mutual stack. Moreover, according to the embodiment, there are prepared a pair of dash side panels 30 (only one shown in Figs. 4 to 6) which have been welded on the width-direction ends of the inner wall 11 of the dash panel 1 in advance and it is executed to unite respective tops of the flange portions 24 to the sidewalls of the so-prepared dash side panels 30 through welds W. While, in the slots 28 of the reinforcement member 4, the lower faces 28b are also welded to the under face of the outer wall 12 of the dash panel 1 through welds W. Thus, not only in the vehicle front/behind direction but also in the vehicle width direction, the dash panel 1 is united with the reinforcement member 4. Meanwhile, the above floor panel 3 may be welded to the dash panel 1 in advance of the above-mentioned assembling procedure. Alternatively, this welding may be carried out after the union between the dash panel 1 and the reinforcement member 4 has been completed. According to the embodiment, since the mutual positioning and temporary fixture between the dash panel 1 and the reinforcement member 4 are accomplished by pinching the width-direction ends of the dash panel 1 between the opposing engagement parts 21 on both sides of the reinforcement member 4, the welding operation can be carried out appropriately and easily. Additionally, as both mutual positioning and temporary fixture do not require any positioning jigs or clamping jigs, it is possible to make a great contribution to the reduction in manufacturing cost of the vehicles. Particularly, since the mutual positioning of the dash panel 1 and the reinforcement member 4 in both vertical and vehicle width directions is accomplished owing to the engagement of the width-direction ends of the dash panel 1 with the positioning parts 22 arranged on both width-direction ends of the reinforcement member 4 and each consisting of the shelf portion 23 and the flange portion 24, it is possible to enhance the stability of positioning. Furthermore, since respective openings of the closed sections in the dash panel 1 in the vehicle width direction are closed by the flange portions 24, it is also possible to elevate the rigidity of side parts of the dash panel 1. With the arrangement where each engagement part 21 is positioned between the shelf portion 23 and the flange portion 24 constituting the positioning part 22, the engagement of the engagement parts 21 can be accomplished at the same time of fitting the width-direction ends of the dash panel 1 to the positioning parts 22, thereby facilitating both of the positioning operation and the temporary fixing operation. Above all, according to the embodiment, each positioning part 22 is substantially L-shaped in its plan view corresponding to the substantially L-shaped notch 25 on each end of the dash panel 1 in the vehicle width direction and the engagement parts 21 are formed in respective positions corresponding to the width-direction edge 25a and the front/behind-direction edge 25b constituting each notch 25. Thus, owing to the provision of the engagement parts 21, it is possible to strictly position the dash panel 1 and the reinforcement member 4 and temporary fix them to each other in the respective directions of up/down, vehicle width and front/behind, thereby further enhancing the stability in positioning and temporary fixing them. Repeatedly, each of the engagement parts 21 includes the flat part 26 partially constituting the shelf portion 23 of the positioning part 22, the taper face 27 formed in the generalized inside face of the flange portion 24 and the slot 28 formed between the flat part 26 and the taper face 27 to engage with the width-direction end of the outer wall 12 of the dash panel 1. Thus, by making the width-direction ends of the dash panel 1 in slide contact with the taper faces 27 from the upside of the reinforcement member 4 and subsequently fitting the ends of the outer wall 12 of the dash panel 1 into the slots 28, then the dash panel 1 can be fixed to the reinforcement member 4 temporarily with no vertical deviation of the former from the latter. Additionally, since the formation of the taper face 27 and the slot 28 in each engagement part 21 does not require any exclusive clipping member, the structure can be simplified,thereby to enlarge the degree of freedom in design,and the manufacturing cost is advantageous because of no increase in the number of elements. In particular, since each slot 28 is formed between the flat part 26 and the taper face 27 to penetrate the reinforcement member 4, it is possible to smoothly lower the width-direction end of the outer wall 12 of the dash panel 1 and fit the above end into the upper face 28a of the slot 28 in assembling the dash panel 1 to the reinforcement member 4. Additionally, the width-direction ends of the outer wall 12 are exposed outside the reinforcement member 4 through the slots 28 under the engagement condition between the outer wall 12 and the slots 28. Thus, the exposure allows the width-direction ends of the outer wall 12 to be welded to respective rims of the slots 28 easily. Note that, in other portions besides the engagement parts 21, it is difficult to weld the dash panel 1 to the positioning parts 22 due to their concealing the width-direction ends of the outer wall 12 from the outside. Especially in the embodiment, since there is ensured a wedge-shaped space S between the slanted lower face 28b of each slot 28 and the under face of the outer wall 12, it is possible to unite the outer wall 12 with the lower face 28b of the slot 28 through the weld W while making use of the space S. In addition to the above welding between the slots 28 and the outer wall 12, the sidewalls of the dash side panels 30 on the dash panel 1 are also welded to the respective upper ends of the flange portions 24 on both sides of the reinforcement member 4 through the welds W. Therefore, the welding rigidity (strength) can be improved between the inner and outer walls 11, 12 of the dash panel 1 and the reinforcement member 4. Furthermore, owing to the positioning of the welds W, the welding operations of both the upper ends of the flange portions 24 and the rims of the slots 28 can be completed while monitoring them from the outside of the vehicle, thereby improving the workability in welding. Further, since the part of flange portion 24 including the taper face 27 is configured with a wall thickness gradually thickened from the top of the flange portion 27 toward the flat part 26, the vicinity of the slot 28 can be provided with high rigidity because of its thickened wall. Therefore, it is possible to enhance the stability in temporary fixing and the joint strength between the width-direction ends of the outer wall 12 of the dash panel 1 and the slots 28. Although the embodiment is directed to the vehicle body structure in the vicinity of the front compartment of the vehicle, the same considerations are applicable to the vehicle body structure in the vicinity of a rear compartment of the vehicle. The dash panel may constitute a partition wall which separates the vehicle cabin and a "power unit" accommodating chamber loaded with an engine, a motor (in case of an electric car), etc. in the rear compartment.

Claims: A vehicle body structure comprising: a panel (1) which is to be arranged in a width direction of the vehicle between a vehicle cabin for passengers and the outside of the vehicle cabin; and a reinforcement member (4) arranged under the said panel (1) to reinforce it from its underside, the reinforcement member (4) being configured to interpose opposite lateral end portions of the panel (1) between opposite lateral end portions of the reinforcement member (4); characterised in that : the panel (1) is a lightweight-metal extrusion having a structure of closed sections and having an inner wall (11) and an outer wall (12); and the reinforcement member (4) is a lightweight-metal casting; and the lateral end portions of the panel (1) and the reinforcement member (4) are provided with means (21) for engagement of the reinforcement member (4) with the panel (1), thereby positioning the reinforcement member (4) and the panel (1) mutually and fixing the panel (1) to the reinforcement member (4) temporarily. A vehicle body structure as claimed in claim 1, wherein the reinforcement member is provided, on each lateral end portion, with a part (22) which has a shelf portion (23) for mounting the corresponding lateral end portion of the panel (1) thereon and a flange portion (24) formed to rise from the shelf portion; and wherein the shelf portion (23) and the flange portion (24) are provided with the engagement means (21). A vehicle body structure as claimed in claim 2, wherein the engagement means (21) comprises: a flat part (26) composed of a part of the shelf portion (23), for mounting the outer wall (12) of the panel (1) thereon; a taper face (27) formed on the flange portion (24) to incline with an open angle ( 2 ) larger than an open angle ( 1 ) of a generalized inside face (24a) of the flange portion (24), the taper face (27) being configured for contact with the inner wall (11) and the outer wall (12) of the panel (1) during sliding movement on the flange portion (24) of the reinforcement member (4); and a slot (28) formed between the flat part (26) and the taper face (27), for engagement with a lateral end of the outer wall (12). A vehicle body structure as claimed in claim 3, wherein the slot (28) is formed to penetrate the reinforcement member (4) obliquely at an angle ( 3 ) substantially bisecting the angle defined by the flat part (26) and the taper face (27), whereby the slot (28) has an upper face (28a) and a lower face (28b) both inclined to the flat part (26). A vehicle body structure as claimed in claim 3 or 4, wherein the flange portion part including the taper face (27) is configured with a wall thickness gradually thickened from the top of the flange portion (24) toward the flat part (26). A vehicle body structure as claimed in any of claims 2 to 5, wherein the panel (1) has a substantially L-shaped notch (25) on each lateral end portion; the positioning part (27) on each lateral end portion of the reinforcement member (4) has a substantially L-shaped configuration in plan view, corresponding to the notch (25); and the engagement means (21) are arranged in respective positions corresponding to one edge defining each notch (25) in a width direction of the vehicle and another edge defining each notch (25) in a front-and-behind direction of the vehicle. A vehicle body structure as claimed in any of claims 3 to 5, further comprising a pair of side panels (30) joined to respective lateral ends of the inner wall (11) of the panel (1) in the width direction of the vehicle, wherein both lateral ends of the outer wall (12) of the panel (1) are fixed to respective rims of the slots (28) through welds, and respective upper ends of the flange portions (24) on both sides of the reinforcement member (4) are fixed to respective side faces of the side panels (30) through welds. A vehicle comprising a vehicle body structure according to any preceding claim. A method of assembling a vehicle body structure according to claim 1, the method comprising: superposing the panel (1) on the reinforcement member (4); positioning the panel (1) and the reinforcement member (4) mutually, thereby putting the panel (1) between the lateral end portions of the reinforcement member (4); sliding the panel (1) on both lateral end portions of the reinforcement member (4); and engaging both lateral end portions of the panel (1) with the reinforcement member (4) through the engagement means (21), thereby temporarily fixing the panel (1) on the reinforcement member (4). A method as claimed in claim 9, wherein the engagement means (21) comprises flat parts (26) for mounting the outer wall (12) of the panel thereon, taper faces (27) configured for contact with the inner wall (11) and the outer wall (12) of the panel during sliding movement, and slots (28) formed between the flat parts (26) and the taper faces (27), for engagement with the ends of the outer wall (12), the method comprising: superposing the panel (1) on the reinforcement member (4); positioning the panel (1) and the reinforcement member (4) mutually, thereby putting the panel (1) between the lateral end portions of the reinforcement member (4); sliding the panel (1) on the taper faces (27); and putting the outer wall (12) of the panel (1) on the flat parts (26) and engaging both lateral end portions of the panel (1) into the slots (28), thereby temporarily fixing the panel (1) on the reinforcement member (4). A method as claimed in claim 9, wherein the panel (1) has substantially L-shaped notches (25) formed on respective lateral end portions of the panel, the lateral end portions of the reinforcement member (4) have substantially L-shaped configurations in plan view, corresponding to the notches (25), and the engagement means (21) are arranged in respective positions corresponding to one edge defining each of the notches in a width direction of the vehicle and another edge defining each of the notches in a front-and-behind direction of the vehicle, the method comprising: superposing the panel (1) on the reinforcement member (4); positioning the panel (1) and the reinforcement member (4) mutually, thereby putting the notches (25) between the substantially L-shaped lateral ends portions of the reinforcement member (4); sliding the panel (1) on both lateral end portions of the reinforcement member (4); and engaging both lateral end portions of the panel (1) with the reinforcement member (4) through the engagement means (21), thereby temporarily fixing the panel (1) on the reinforcement member (4). A method as claimed in any of claims 9 to 11, wherein a pair of side panels (30) are joined to respective lateral ends of the inner wall (11) of the panel (1), further comprising: welding the ends of the inner wall (11) of the panel (1) to the engagement means (21) and further welding the side panels (30) to both sides of the reinforcement member (4), thereby formally fixing the panel (1) on the reinforcement member (4).

Inventors: SATO MANABU, SATO, MANABU
Applicants: NISSAN MOTOR, NISSAN MOTOR COMPANY, LIMITED
Application year: 2000
Main classification: B62D29
IPC codes: B62D29, B62D21, B62D25, B62D27