Front structure of vehicle body

In a front structure of a vehicle body having a cowl box, the cowl box is formed by a closed cross-section windshield holding member for holding the windshield, a front cowl plate and a dashboard upper panel. The front cowl plate defines the front face of the cowl box and the dashboard upper panel defines the bottom and the rear face of the same. The windshield holding member and the dashboard upper panel separate upon vehicle impact and resultant cowl box deformation such that the windshield and holding member remain engaged.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to a front structure of a vehicle body, and more 
particularly to a front structure of a vehicle body having a cowl box 
under the windshield. 
2. Description of the Prior Art 
As described in Japanese Unexamined Utility Model Publication No. 
56(1981)-168441, there has been known a front structure of a vehicle body 
in which a cowl box is provided to extend in the direction of the width of 
the vehicle body along the lower edge of the windshield. That is, as shown 
in FIG. 6, a dashboard upper panel C and a front cowl plate D are disposed 
below the space between the lower edge of the windshield A and the rear 
edge of the hood B to extend in the direction of the width of the vehicle 
body. The dashboard upper panel C and the front cowl plate D define a cowl 
box G separated from both the passenger compartment E and the engine 
compartment F. The cowl box G is generally provided to ensure a vehicle 
body rigidity and/or to introduce the fresh air into the passenger 
compartment. Conventionally, the dashboard upper panel C, which defines 
the bottom and the rear face of the cowl box G, and the front cowl plate 
D, which defines the front face and the top face of the same, are fixed 
together such as by spot welding, for instance, flange portions C1 and C2 
respectively formed on the front and rear portions of the panel C to the 
flange portions D1 and D2 respectively formed on the front and rear 
portions of the plate D. A weather strip H is mounted on the rear junction 
of the panel C and the plate D, i.e., the flange portions C2 and D2, and 
the lower edge of the windshield A is engaged with the weather strip H so 
that the windshield A is supported by the cowl box G. 
However, this structure is disadvantageous in that when a collision forces 
the engine rearward, pushing the cowl box G toward the passenger 
compartment E, there is a possibility that the portion of the cowl box G 
supporting the windshield A will be deformed or the lower edge of the 
windshield A disengaged therefrom, thereby breaking the windshield A. This 
is undesirable in terms of passenger safety. 
SUMMARY OF THE INVENTION 
In view of the foregoing observations and description, the primary object 
of the present invention is to provide an improved front structure of a 
vehicle body having a cowl box in which breakage of the windshield due to 
deformation or displacement of the cowl box upon collision can be 
prevented, thereby providing improved passenger safety. 
In accordance with the present invention, the cowl box is formed by a 
windshield holding member for holding the windshield, a front cowl plate 
and a dashboard upper panel, the front cowl plate defining the front face 
of the cowl box and the dashboard upper panel defining the bottom and the 
rear face of the same, and the junction of the windshield holding member 
with the dashboard upper panel is more fragile than the other junctions. 
The windshield holding member and the dashboard upper panel may be fixed 
to each other by bolts or spot welding, for instance. In the case that the 
windshield holding member and the dashboard upper panel are fixed by bolts 
passed through bolt holes in the windshield holding member and the 
dashboard upper panel, the junction therebetween can be made more fragile 
than the other junctions by, for instance, cutting a part of the wall 
defining the bolt holes of the windshield holding member or the dashboard 
upper panel so that the bolts can be dislodged from the bolt holes. In the 
case that the windshield holding member and the dashboard upper panel are 
fixed by spot welding, the junction therebetween can be made more fragile 
by, for instance, welding together the windshield holding member and the 
dashboard upper panel at spots spread thinner than in the other junctions 
between other portions of the cowl box. 
With the arrangement described above, the dashboard upper panel is 
dislodged from the windshield holding member when a collision forces the 
engine rearward, pushing the cowl box toward the passenger compartment, 
with the windshield holding member remaining in the original position. 
Breakage of the windshield due to deformation or displacement of the cowl 
box upon collision can be prevented, eliminating the risk of the passenger 
being hurt by windshield fragments.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
In FIGS. 1 and 2, a vehicle 1 is provided with a cowl box 6 formed below 
the space between the rear edge of a hood 2 and the lower edge of a 
windshield 3. The cowl box 6 is separated from an engine compartment 4 and 
a passenger compartment 5. The cowl box 6 comprises a front cowl plate 7 
which extends in the direction of the width of the vehicle body and forms 
the front face of the cowl box 6, a windshield holding member 8 provided 
to form an upper part of the cowl box 6 and to support the windshield 3, 
and dashboard upper panel 9 which is fixed to the front cowl plate 7 and 
the windshield holding member 8 respectively at the front edge and the 
upper edge thereof and forms the bottom face and the rear face of the cowl 
box 6. A dashboard lower panel 10 for separating the engine compartment 4 
from the passenger compartment 5 is fixed to the lower surface of the 
front edge portion of the dashboard upper panel 9. The windshield holding 
member 8 comprises an upper member 11 and a lower member 12 fixed together 
relatively strongly by, for instance, spot welding to form a closed cross 
section in the direction of the width of the vehicle body. The upper 
surface of the front edge portion of the windshield holding member 8 is 
fixed to the lower edge portion of the windshield 3 by adhesive 13 to hold 
the windshield 3. 
A link mechanism 15 (partly shown in FIG. 1) for driving a windshield wiper 
14 is housed in the cowl box 6. The link mechanism 15 is supported on the 
windshield holding member 8 by way of a bracket 16 mounted thereon, and is 
driven by an electric motor (not shown). In this particular embodiment, an 
engine 17 having a surge tank 17a on the rear side thereof is provided in 
the engine compartment 4, and a seal member 18 for sealing the space 
between the hood 2 and the front cowl plate 7 is mounted on the upper edge 
of the front cowl plate 7. 
The windshield holding member 8 and the dashboard upper panel 9 are fixed 
together by a plurality of bolts 19 more fragilely than other junctions, 
e.g., the junction of the front cowl plate 7 and the dashboard upper panel 
9. That is, as shown in an enlarged scale in FIGS. 3 and 4, the rear face 
12a of the lower member 12 of the windshield holding member 8 is provided 
with a plurality of bolt insertion portions 12b and the upper edge portion 
9a of the dashboard upper panel 9 is provided with a plurality of bolt 
insertion portions 9b. The bolt insertion portions 12b and 9b are the same 
in number and each of the bolt insertion portions 12b of the lower member 
12 is aligned with one of the bolt insertion portions 9b of the dashboard 
upper panel 9. The bolts 19 are inserted into the aligned bolt insertion 
portions 12b and 9b and a plurality of nuts 20 are screwed on the bolts 19 
from behind the rear face 12a of the lower member 12. By tightening the 
bolts 19, the windshield holding member 8 and the dashboard upper panel 9 
are fixed together. Each of the bolt insertion portions 12b is in the form 
of an opening. On the other hand, each of the bolt insertion portions 9b 
of the dashboard upper panel 9 is in the form of an open slot an end of 
which opens at the upper edge of the dashboard upper panel 9. Thus, the 
junction of the windshield holding member 8 and the dashboard upper panel 
9 is relatively fragile. That is, when the dashboard upper panel 9 is 
pushed toward the passenger compartment 5 by the engine 17 by a collision, 
the bolts 19 are dislodged from the bolt insertion portions 9b of the 
dashboard upper panel 9 and the dashboard upper panel 9 is separated from 
the windshield holding member 8. 
With this arrangement, when upon collision the engine 17 is moved into the 
passenger compartment 5 as shown by the chained line in FIG. 1, the front 
cowl plate 7, the dashboard lower panel 10 and the dashboard upper panel 9 
are deformed by the engine 17 (the surge tank l7a in this particular 
embodiment) toward the passenger compartment 5. However, the windshield 
holding member 8 remains in the original position, dislodged from the 
dashboard upper panel 9 since the windshield holding member 8 and the 
dashboard upper panel 9 are fixed together relatively fragilely. That is, 
when the dashboard upper panel 9 is pushed toward the passenger 
compartment 5, the upper edge portion 9a of the dashboard upper panel 9 is 
pulled downwardly as shown by the chained line in FIGS. 1 and 4. 
Accordingly, the upper edge portion 9a is dislodged from the bolts 19 
since the bolt insertion portions 9b are open at the upper edge thereof. 
Since the windshield holding member 8 can remain in the original position 
even if the dashboard upper panel 9 is displaced toward the passenger 
compartment 5, deformation of the windshield holding member 8 or removal 
of the windshield 3 from the windshield holding member 8 can be avoided 
and, accordingly, the windshield 3 can be prevented from being broken. 
Though, in the first embodiment, the windshield holding member 8 and the 
dashboard upper panel 9 are fixed together relatively fragilely by using 
open slots as the bolt insertion portions 9b of the dashboard upper panel 
9 so that the windshield holding member 8 is dislodged from the dashboard 
upper panel with the bolts 19 and the nuts 20 held by the windshield 
holding member 8, the bolt insertion portions 12b of the windshield 
holding member 8 may instead be in the form of open slots with the bolt 
insertion portions 9b of the dashboard upper panel 9 being in the form of 
openings so that the windshield holding member is dislodged from the 
dashboard upper panel 9 with the bolts 19 and the nuts 20 held by the 
dashboard upper panel 9. 
In the second embodiment shown in FIG. 5, the windshield holding member 8' 
and the dashboard upper panel 9' are fixed together by spot welding. That 
is, the windshield holding member 8' and the dashboard upper panel 9' are 
welded at spots a' and the junction thereof is made relatively fragile by 
increasing the spot pitch 1' as compared with the other junctions. In this 
case, it is preferred that the spot pitch 1' be enlarged at a portion at 
which the windshield holding member 8' is especially apt to be deformed, 
or a portion at which the engine 17 is apt to be moved toward the 
passenger compartment 5 (the central portion in the illustrated 
embodiment). 
The windshield holding member and the dashboard upper panel may be fixed 
together fragilely by a seal member formed of, for instance, adhesive 
instead of using bolts or spot welding. Further, it is possible to fix the 
windshield holding member to the dashboard upper panel more fragilely than 
is the case with other junctions by a combination of these bonding methods 
.