JP4075450B2 - Car cowl box structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a cowl box structure that has both a function as a vehicle width direction skeleton member of a vehicle body front portion and a function as an outside air introduction portion of an in-vehicle air conditioning unit, which are arranged to extend in the vehicle width direction at a front portion of an automobile. .
[0002]
[Prior art]
Since the cowl box functions as a skeleton member in the vehicle width direction of the vehicle body front portion as described above, the lower end portion of the front window panel is fixedly supported on the cowl box.
[0003]
[Problems to be solved by the invention]
However, because the cowl box has a closed cross-sectional structure, the support rigidity of the front window panel is high, and when an external load is input near the front window panel support from above, the reaction force against the input load increases and the impact energy is effective. Cannot be absorbed.
[0004]
Therefore, it is also known that the cowl box has an open cross section in front of the support part at the lower end of the front window panel. However, when the cowl box has an open cross section structure, the rigidity of the vehicle body is inevitably lowered. In addition, due to the decrease in the rigidity of the vehicle body, there is a problem that a booming noise is likely to occur during idle vibration.
[0005]
Accordingly, the present invention provides a cowl box structure for an automobile capable of achieving both the maintenance of vehicle body rigidity and the improvement of impact energy absorption efficiency against an input load.
[0006]
[Means for Solving the Problems]
According to the first aspect of the present invention, in the cowl box structure of an automobile that extends in the vehicle width direction and supports the lower end portion of the front window panel at the front portion of the vehicle body, the lower end portion of the front window panel is positioned on the front edge side. Is fixed to the front end of the support panel with a free end to form a cantilever, and a closed cross-section cowl box is formed at a predetermined interval below the front end of the support panel. The front end portion and the cowl box are connected to each other by a stay member at a position that is at least an antinode when the front window panel vibrates or in the vicinity thereof .
[0008]
According to the invention of claim 2 , in the cowl box structure of the automobile according to claim 1 , the connecting position of the front end portion of the support panel and the cowl box is set to the full width from both ends in the vehicle width direction of the lower end portion of the front window panel. It is characterized in that it is set at a position close to the inner side by about 1/4 and a substantially central position in the vehicle width direction.
[0009]
【The invention's effect】
According to the first aspect of the present invention, the fixed support portion at the lower end portion of the front window panel is configured as a cantilever, so that an external load from above is input to the vicinity of the support portion of the front window panel. Thus, the support panel can be easily deformed. On the other hand, since a cowl box having a closed cross section exists below the support panel, it is possible to prevent the vehicle body rigidity from being lowered.
[0010]
Further, since a predetermined interval is provided between the support panel and the closed cross section air box, a sufficient amount of deformation of the support panel with respect to the input load is ensured, and the impact energy absorption efficiency with respect to the input load is increased. It can be raised enough.
[0011]
Further, since the rigidity of the vehicle body can be maintained with the cowl box as a closed cross section, it is possible to prevent the occurrence of a booming noise during idling vibration or the like.
[0012]
Further , since the front end of the support panel and the cowl box having a closed cross section are connected by a stay member at least at a position where the front window panel vibrates or at a position near it, the front window panel vibrates. Because the high-amplitude cowl box can support the increased amplitude at the time, the vibration at the lower end of the front window panel can be effectively suppressed, and as a result, the noise caused by body vibration that occurs during idling can be reduced. Can do.
[0013]
Further, since the support panel is partially fixed to the cowl box having a closed cross section, the vehicle body rigidity can be further improved.
[0014]
According to the second aspect of the present invention, in addition to the effect of the first aspect , the connecting position of the support panel and the cowl box is set to approximately ¼ of the full width from both ends in the vehicle width direction of the lower end portion of the front window panel. Since the front window panel vibrates with the both ends in the vehicle width direction as fixed points, the primary mode or the secondary mode has a particularly remarkable amplitude. Vibration can be effectively suppressed.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0016]
1 and 2 show a first embodiment of a cowl box structure according to the present invention. FIG. 1 is a perspective view of the cowl portion viewed from the front of the vehicle with the engine hood removed, and FIG. 2 is a line AA in FIG. It is an expanded sectional view of the position corresponding to.
[0017]
A cowl portion 11 is formed in the vehicle width direction at the front portion of the automobile M shown in FIG.
[0018]
The cowl portion 11 includes a dash upper panel 15 and a cowl front panel 16, and a support panel 12 projecting forward of the vehicle is joined and fixed to an upper end portion of the dash upper panel 15, and a front edge of the support panel 12 is a free end. As the portion 12 a, the free end portion 12 a is bent along the inclination angle of the front window panel 10.
[0019]
The lower end portion 10a of the front window panel 10 is bonded and fixed to the inclined free end portion 12a of the support panel 12 with an adhesive material 13 to form a cantilever.
[0020]
The inner wall of the dash upper panel 15 is spot welded with a partition wall 20 having a square cross section across the bottom wall 15a and the vertical wall 15b, thereby lowering the vehicle width to the lower side of the front end portion of the support panel 12. A cowl box 21 having a closed cross-sectional structure extending in the direction is configured.
[0021]
At this time, a predetermined interval L is provided between the cowl box 21 and the front end portion 12a of the support panel 12 constituting the cantilever, and the predetermined interval L supports and fixes the lower end portion 10a of the front window panel 10. It is determined by the amount of deformation required for the front end portion 12a of the support panel 12 with respect to the magnitude of the input load around the portion, and an interval L dimension greater than the amount of deformation is provided.
[0022]
The lower end portion 16 a of the cowl front panel 16 is spot-welded to the overlapping portion of the front side edge of the bottom wall 15 a and the front end portion of the partition wall 20, thereby forming a trough structure 17 having a U-shaped cross section between the partition wall 20. The rear end portion of the hood 19 is in liquid-tight contact with the upper end portion 16b of the cowl front panel 16 with a weather strip 18 interposed therebetween. The rear end portion of the hood 19 and the window panel 10 are in contact with each other. An appropriate space S is provided between the lower end portion 10a and the outside air and rainwater that has flowed down the front window panel 10 surface.
[0023]
In the cowl box structure according to the present embodiment having the above configuration, the lower end portion 10a of the front window panel 10 is bonded and fixed to the free end portion 12a of the support panel 12 to form a cantilever. The support panel 12 can be easily deformed with respect to an external load from above, for example, an input load F from the impactor H, which is input around the support fixing portion of the lower end portion 10 a of the window panel 10.
[0024]
On the other hand, since the cowl box 21 having a closed cross section exists below the support panel 12, it is possible to prevent the vehicle body rigidity from being lowered by the cowl box 21 having the closed cross section.
[0025]
And since the predetermined space | interval L is provided between the said support panel 12 and the cowl box 21 of the said closed cross section, the deformation amount of the support panel 12 with respect to the said input load F can fully be ensured, and the input of this load F is possible. The absorption efficiency of impact energy against can be increased.
[0026]
Further, as described above, the rigidity of the vehicle body can be maintained with the cowl box 21 as a closed cross section, so that it is possible to prevent the occurrence of a booming noise during idle vibration or the like.
[0027]
3 and 4 show a second embodiment of the present invention, in which the same components as in the first embodiment are denoted by the same reference numerals and redundant description is omitted.
[0028]
FIG. 3 is an enlarged cross-sectional view of a position corresponding to line BB in FIG. 1 shown in the first embodiment, and FIG. 4 is a plan view showing a vibration mode of the lower end portion of the front window panel.
[0029]
In the second embodiment, the front end portion 12a of the support panel 12 and the cowl box 21 having a closed cross section constituting the cantilever in the first embodiment are positioned at a position where the front window panel 10 becomes a belly when membrane vibration occurs. They are connected by stay members 22.
[0030]
That is, in the second embodiment, for the secondary mode vibration of the membrane vibration, the support panel 12 and the cowl box 21 are set to approximately 1/4 of the full width from both ends in the vehicle width direction of the lower end portion 10a of the front window panel 10. They are welded and connected via the stay member 22 at the positions close to the inside.
[0031]
Therefore, in the cowl box structure of the second embodiment, as shown in FIG. 4, when the front window panel 10 vibrates with both ends in the vehicle width direction as fixed points K1, K2, the amplitude increasing portion is the closed cross-section cowl box 21. Therefore, it is possible to effectively suppress the vibration of the front window panel 10 and to reduce the noise caused by the vibration of the vehicle body generated during idling.
[0032]
That is, the vibration mode of the front window panel 10 is shown in FIG. 4. In this case, in the primary mode of the membrane vibration indicated by the broken line in the figure, the front window panel 10 uses the fixed points K1 and K2 at both ends in the vehicle width direction as nodes. The vehicle will vibrate, and the central part C0 in the vehicle width direction becomes a belly and becomes a place of maximum amplitude W1.
[0033]
Further, in the secondary mode of membrane vibration indicated by the alternate long and short dash line in the figure, the fixed points K1 and K2 and the central part C0 vibrate as nodes, respectively, so that they are inward from the both ends in the vehicle width direction by about 1/4 of the full width. The offset positions C1 and C2 become antinodes and have a maximum amplitude W2.
[0034]
Therefore, in the second embodiment, the connecting position of the support panel 12 and the cowl box 21 by the stay member 22 is a position that is inward from the both ends in the vehicle width direction by about 1/4 of the full width, that is, the abdomen of the secondary mode. Since it is the minute (C1, C2), the vibration of the secondary mode of the front window panel 10 can be effectively suppressed, and consequently, the noise caused by idle vibration can be reduced most efficiently.
[0035]
Further, the stay member 22 is provided at a position that is approximately ¼ of the full width from both ends in the vehicle width direction. This is because the position of the maximum amplitude W1 is also provided for the vibration in the primary mode with the central portion C0 as an antinode. Even if not, it is a place where a certain large amplitude is generated, and the vibration suppressing effect can be exhibited even for the vibration of the primary mode.
[0036]
The connection position of the support panel 12 and the cowl box 21 is not limited to the positions (C1, C2) that are substantially inward from the both ends in the vehicle width direction by about 1/4 of the entire width, and the primary mode vibration is applied. Only the position of the center portion C0 in the vehicle width direction can be set as a target, or the center portion C0 and the 1/4 positions C1 and C2 can be set at respective positions.
[0037]
By the way, although the cowl box structure of the present invention has been described by taking the examples of the first and second embodiments, various embodiments can be adopted without departing from the gist of the present invention. .
[Brief description of the drawings]
FIG. 1 is a perspective view of a cowl portion viewed from the front of a vehicle with a hood removed in a first embodiment of the present invention.
FIG. 2 is an enlarged cross-sectional view of a position corresponding to the line AA in FIG.
FIG. 3 is an enlarged cross-sectional view corresponding to FIG. 1 in a second embodiment of the present invention.
FIG. 4 is a plan view showing a vibration mode of a lower end portion of a front window glass in a second embodiment of the present invention.
[Explanation of symbols]
10 front window panel 11 cowl part 12 support panel 12a free end part 21 cowl box 22 stay member

Claims (2)

In the cowl box structure of an automobile that is arranged to extend in the vehicle width direction at the front part of the vehicle body and supports the lower end part of the front window panel,
The lower end of the front window panel is fixed to the front end of the support panel with the front edge side as a free end to form a cantilever, and a closed section is provided at a predetermined interval below the front end of the support panel. the cowl box form,
A cowl box structure for an automobile, wherein a front end portion of the support panel and the cowl box are connected by a stay member at least at a position where the front window panel is subjected to membrane vibration, or at a position in the vicinity thereof . The connection position between the front end of the support panel and the cowl box is set at a position that is approximately 1/4 of the full width from both ends in the vehicle width direction at the lower end of the front window panel and at a substantially center position in the vehicle width direction. The automobile cowl box structure according to claim 1 .

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