Abstract:
To provide a defroster duct comprising a duct body defining an air passage which has an inlet in an upstream end of the air passage, and an outlet in a downstream end of the air passage, the duct body configured to flow an air toward a windshield of a vehicle via the outlet, wherein an inner face of the duct body defining a first face and a second face opposite to the first face, wherein the duct body including a wind direction-changing rib extending from the first face toward the second face and having no contact with the second face.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is based upon and claims the benefit of priority from prior Japanese Patent Application P2006-136781 filed on May 16, 2006; the entire contents of which are incorporated by reference herein.  
       BACKGROUND OF THE INVENTION  
       [0002]     The present invention relates to a defroster duct from which conditioned air flows out toward a windshield.  
         [0003]     Japanese Patent Application Laid-open No. H10-236153 discloses a conventional defroster duct similar to the present invention. As shown in  FIG. 1 , a defroster duct  100  includes a duct body  101  in which air passages  101   c  are formed. One ends of the air passages  101   c  are formed with inlets  101   a  and the other ends of the air passages  101   c  are formed with outlets  101   b . The defroster duct  100  also includes a pair of left and right wind direction-changing ribs  102  which branch the air passages  101   c  of the duct body  101 . An air conditioning unit  103  is connected to the inlets  101   a , and conditioned air of desired temperature is introduced from the air conditioning unit  103 . The outlets  101   b  are opened at an instrument panel (not shown) of a lower end of the windshield (not shown).  
         [0004]     The pair of left and right wind direction-changing ribs  102  are straight in shape, and are inclined such that a distance therebetween is gradually increased. The wind direction-changing ribs  102  completely divide the air passages  101   c  into three.  
         [0005]     According to the conventional example, the wind direction-changing ribs  102  guide the conditioned air introduced from the inlets  101   a  in such a manner that the conditioned air is spread in a form of a fan as a whole. Thus, a blowing distribution from the outlet  101   b  can be made wide.  
         [0006]     However, according to the conventional defroster duct  100 , since the wind direction-changing ribs  102  completely divide the air passages  101   c , there is a possibility that a no-wind region is generated around the wind direction-changing ribs  102 , and as a result, wind velocity is reduced. Therefore, although the blowing distribution is wide, a range far from the outlet  101   b  can not be covered.  
         [0007]     Further, since the wind directions of all of the conditioned air are the same, a so-called valley of blowing out air flow is generated downstream of the wind direction-changing ribs  102 . Thus, although the blowing distribution is wide, the blowing distribution becomes partially uneven.  
       SUMMARY OF THE INVENTION  
       [0008]     It is an object of the present invention to provide a defroster duct capable of covering a range where the blowing out flow from the outlet is wide and far from the outlet, and capable of achieving even blowing distribution.  
         [0009]     An aspect of the present invention provides a defroster duct comprising a duct body defining an air passage which has an inlet in an upstream end of the air passage, and an outlet in a downstream end of the air passage, the duct body configured to flow an air toward a windshield of a vehicle via the outlet, wherein an inner face of the duct body defining a first face and a second face opposite to the first face, wherein the duct body including a wind direction-changing rib extending from the first face toward the second face and having no contact with the second face. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]      FIG. 1  is a perspective view of a conventional defroster duct;  
         [0011]      FIG. 2  is a schematic diagram of a vehicle and shows an embodiment of the present invention;  
         [0012]      FIG. 3  is a diagram of an instrument panel as viewed from a driver and shows the embodiment;  
         [0013]      FIG. 4  is a front view of a defroster duct and a windshield and shows the embodiment;  
         [0014]      FIG. 5  is a sectional view taken along the line V-V in  FIG. 4  and shows the embodiment;  
         [0015]      FIG. 6  is an enlarged view of a wind direction-changing rib and shows the embodiment;  
         [0016]      FIG. 7  is an enlarged view of a portion VII in  FIG. 5  and shows the embodiment;  
         [0017]      FIG. 8  is a diagram of a wind direction-changing flow and a rib-crossing flow and shows the embodiment; and  
         [0018]      FIG. 9  is a front view of a defroster duct and a windshield according to another embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0019]     Embodiments of the present invention are explained below with reference to the drawings.  
       First Embodiment  
       [0020]     FIGS.  2  to  8  show a first embodiment of the present invention, where  FIG. 2  is a schematic diagram of a vehicle,  FIG. 3  is a diagram of an instrument panel as viewed from a driver,  FIG. 4  is a front view of a defroster duct and a windshield,  FIG. 5  is a sectional view taken along the line V-V in  FIG. 4 ,  FIG. 6  is an enlarged view of a wind direction-changing rib,  FIG. 7  is an enlarged view of a portion VII in  FIG. 5 , and  FIG. 8  is a diagram of a wind direction-changing flow and a rib-crossing flow.  
         [0021]     As shown in  FIG. 2 , a front portion of a passenger room of a vehicle  1  is covered with a windshield  2 . An instrument panel  3  is disposed on a vehicle side of a lower end of the windshield  2 . An air conditioning unit  4  is disposed below the instrument panel  3 . The air conditioning unit  4  generates conditioned air of a predetermined temperature, and the generated conditioned air is sent out into the passenger room through various ducts such as a defroster duct  10 .  
         [0022]     As shown in  FIG. 3 , the defroster duct  10  includes a front duct portion  11  and side duct portions  12 . The front duct portion  11  clears the fogging of the windshield  2 , and the side duct portions  12  clear the fogging on the side of the side glass. A structure of the front duct portion  11  will be explained below.  
         [0023]     As shown in  FIG. 4 , the front duct portion  11  includes a pair of left and right branch duct portions  11   a  and  11   b  due to other car-mounted part disposing spaces. Each of the branch duct portions  11   a  and  11   b  includes a duct body  16  provided therein with an air passage  15 , and a plurality of wind direction-changing ribs  17  provided in the air passage  15  of the duct body  16 . One end of the air passage  15  is provided with an inlet  13 , and the other end of the air passage  15  is provided with an outlet  14 .  
         [0024]     An air conditioning unit  4  is connected to the inlet  13 , and conditioned air having a desired temperature is introduced by the air conditioning unit  4 . The outlet  14  opens at the instrument panel  3  (shown in  FIGS. 2 and 3 ) at a lower end of the windshield  2 .  
         [0025]     Each of the inlets  13  is formed into a narrow size D 1  (shown in  FIG. 4 ) in the widthwise direction of the vehicle, and the outlet  14  is formed into a wide size D 2  (shown in  FIG. 4 ) in the widthwise direction of the vehicle due to other car-mounted part disposing spaces. The inlet  13  is formed into a wide size (shown in  FIG. 5 ) in the longitudinal direction of the vehicle, and the outlet  14  is formed into a narrow size D 4  (shown in  FIG. 5 ) in the longitudinal direction of the vehicle. A cross-sectional area of the inlet  13  and a cross-sectional area of the outlet  14  are substantially the same with each other.  
         [0026]     The two wind direction-changing ribs  17  are disposed at two locations in the air passages  15 . As shown in  FIG. 5 , if an inner surface of the duct body  16  which forms the air passage  15  and along which the conditioned air a mainly flows is defined as a first surface  16   a , and an inner surface of the duct body  16  which is opposed to the first surface  16   a  is defined as a second surface  16   b , each wind direction-changing rib  17  is set such that the wind direction-changing rib  17  projects from the first surface  16   a  toward the second surface  16   b  but does not reach the second surface  16   b . If a height of the air passage  15  is defined as H, a height h of the wind direction-changing rib  17  is set in a range of ⅓·H to ⅔·H.  
         [0027]     As shown in  FIG. 6 , each wind direction-changing rib  17  includes a straight rib portion  17   a  extending along a direction of the main flow of the conditioned air a introduced from the inlet  13 , and a curved rib portion  17   b  which is continuous with the downstream end of the straight rib portion  17   a  and gradually bent or curved in a desired direction with respect to the direction of the main flow of the conditioned air a.  
         [0028]     As shown in  FIG. 7 , a height of the downstream end of the wind direction-changing rib  17  is smoothly reduced toward the downstream, and the height of the most downstream end is zero. That is, if the downstream end of the wind direction-changing rib  17  is formed as indicated by the broken line in  FIG. 7 , a step is formed at a location of the most downstream end, however, the step is not actually formed.  
         [0029]     In the configuration described above, since each wind direction-changing rib  17  guides the conditioned air a introduced from the inlet  13  such that the entire conditioned air spreads, the blowing distribution from the outlet  14  becomes wide.  
         [0030]     The flow of the conditioned air a in the air passage  15  will be explained in more detail. As shown in  FIGS. 5 and 8 , the main flow of the conditioned air a introduced into the air passage  15  travels near the first surface  16   a , the main flow becomes a wind direction-changing flow b which travels while changing the wind direction by the wind direction-changing rib  17 , and conditioned air a other than the main flow travels near the second surface  16   b  and thus becomes a rib-crossing flow c which travels without changing the wind direction by the wind direction-changing rib  17 . Therefore, no-wind region is not generated around the wind direction-changing rib  17  and as a result, the air travels without reducing the wind velocity. Further, since air flows having different traveling directions, i.e., the wind direction-changing flow b and the rib-crossing flow c flow out from the outlet  14 , no-wind region, i.e., a so-called valley of blowing out air flow is not generated downstream of the wind direction-changing rib  17 . From the above reason, the blowing out wind from the outlet  14  has a wide range and a range far from the outlet  14  can be covered, and even blowing distribution can be achieved. In  FIG. 4 , wind velocity regions such as blowing out wind are indicated by broken lines, and the broken line at a position above a point shows an effective wind velocity value reaching region.  
         [0031]     Since the wind direction-changing rib  17  does not completely divide the air passage  15 , the blowing air resistance of the wind direction-changing rib  17  becomes small and thus, it is possible to prevent the wind velocity from being reduced.  
         [0032]     In the present embodiment, each the wind direction-changing rib  17  includes the straight rib portion  17   a  extending along the direction of the main flow of the conditioned air a, and the curved rib portion  17   b  which is continuous with the downstream end of the straight rib portion  17   a  and gradually bent or curved in the desired direction with respect to the direction of the main flow of the conditioned air a. Therefore, the main flow of the conditioned air a travels while being guided by the straight rib portion  17   a  and then, its wind direction is smoothly changed by the curved rib portion  17   b . Thus, a noise caused by peeling off of the conditioned air generated when the wind direction of the conditioned air is abruptly changed is not generated.  
         [0033]     In the present embodiment, the height of the downstream end of the wind direction-changing rib  17  is smoothly reduced toward downstream, and the height of the most downstream end becomes zero. Therefore, since separation of wind is not generated downstream of the wind direction-changing rib, it is possible to reliably prevent no-wind region (that is, a valley of blowing out air flow) from being generated in the blowing out air.  
         [0034]     In the present embodiment, the inlet  13  is narrow in width in a widthwise direction of a vehicle, the outlet  14  is wide in the widthwise direction of the vehicle, the inlet  13  is wide in a longitudinal direction of the vehicle, the outlet  14  is narrow in the longitudinal direction of the vehicle, a cross-sectional area of the inlet  13  is substantially equal to a cross-sectional area of the outlet  14 . Therefore, it is possible to prevent the flowing velocity of the conditioned air from being reduced in the air passage  15  as small as possible. Thus, the blowing out speed of the conditioned air can be maintained at a predetermined speed. Thus, it is possible to prevent a fogging-clearing range of the windshield  2  from becoming narrow and to prevent the fogging-clearing speed from being reduced.  
       Second Embodiment  
       [0035]      FIG. 9  is a front view of a defroster duct and a windshield according to second embodiment of the present invention. The front duct portion  11  of the previous embodiment is a vertically long. A front duct  11 A shown in  FIG. 9  is a laterally long and this point is different. With this different point, a wind direction-changing rib  17 A is set such that a wind direction of conditioned air is changed in a direction in which the conditioned air is prevented from spreading. Other structures are identical to that of the previous embodiment, and therefore redundant explanations thereof will be omitted. Also with the present embodiment, the same effect as that of the previous embodiment can be obtained.  
         [0036]     While the embodiments of the present invention have been described above, the invention is not limited to the above embodiments and changes and modifications can be made within the scope of the gist of the present invention.  
         [0037]     For example, each of the wind direction-changing ribs  17  and  17 A according to the above embodiments includes the straight rib portion  17   a  and the curved rib portion  17   b , but a portion of the wind direction-changing rib where it is unnecessary to change the wind direction or it is unnecessary to largely change the wind direction may comprise only a straight portion.